Notes for windows users postgresql

Connecting to a Database

psql is a regular PostgreSQL client application. In order to connect to a database you need to know the name of your target database, the host name and port number of the server, and what database user name you want to connect as. psql can be told about those parameters via command line options, namely -d, -h, -p, and -U respectively. If an argument is found that does not belong to any option it will be interpreted as the database name (or the database user name, if the database name is already given). Not all of these options are required; there are useful defaults. If you omit the host name, psql will connect via a Unix-domain socket to a server on the local host, or via TCP/IP to localhost on Windows. The default port number is determined at compile time. Since the database server uses the same default, you will not have to specify the port in most cases. The default database user name is your operating-system user name. Once the database user name is determined, it is used as the default database name. Note that you cannot just connect to any database under any database user name. Your database administrator should have informed you about your access rights.

When the defaults aren’t quite right, you can save yourself some typing by setting the environment variables PGDATABASE, PGHOST, PGPORT and/or PGUSER to appropriate values. (For additional environment variables, see Section 34.15.) It is also convenient to have a ~/.pgpass file to avoid regularly having to type in passwords. See Section 34.16 for more information.

An alternative way to specify connection parameters is in a conninfo string or a URI, which is used instead of a database name. This mechanism give you very wide control over the connection. For example:

$ psql "service=myservice sslmode=require"
$ psql postgresql://dbmaster:5433/mydb?sslmode=require

This way you can also use LDAP for connection parameter lookup as described in Section 34.18. See Section 34.1.2 for more information on all the available connection options.

If the connection could not be made for any reason (e.g., insufficient privileges, server is not running on the targeted host, etc.), psql will return an error and terminate.

If both standard input and standard output are a terminal, then psql sets the client encoding to auto, which will detect the appropriate client encoding from the locale settings (LC_CTYPE environment variable on Unix systems). If this doesn’t work out as expected, the client encoding can be overridden using the environment variable PGCLIENTENCODING.

Entering SQL Commands

In normal operation, psql provides a prompt with the name of the database to which psql is currently connected, followed by the string =>. For example:

$ psql testdb
psql (16.0)
Type "help" for help.

testdb=>

At the prompt, the user can type in SQL commands. Ordinarily, input lines are sent to the server when a command-terminating semicolon is reached. An end of line does not terminate a command. Thus commands can be spread over several lines for clarity. If the command was sent and executed without error, the results of the command are displayed on the screen.

If untrusted users have access to a database that has not adopted a secure schema usage pattern, begin your session by removing publicly-writable schemas from search_path. One can add options=-csearch_path= to the connection string or issue SELECT pg_catalog.set_config('search_path', '', false) before other SQL commands. This consideration is not specific to psql; it applies to every interface for executing arbitrary SQL commands.

Whenever a command is executed, psql also polls for asynchronous notification events generated by LISTEN and NOTIFY.

While C-style block comments are passed to the server for processing and removal, SQL-standard comments are removed by psql.

Advanced Features

Variables

psql provides variable substitution features similar to common Unix command shells. Variables are simply name/value pairs, where the value can be any string of any length. The name must consist of letters (including non-Latin letters), digits, and underscores.

To set a variable, use the psql meta-command \set. For example,

testdb=> \set foo bar

sets the variable foo to the value bar. To retrieve the content of the variable, precede the name with a colon, for example:

testdb=> \echo :foo
bar

This works in both regular SQL commands and meta-commands; there is more detail in SQL Interpolation, below.

If you call \set without a second argument, the variable is set to an empty-string value. To unset (i.e., delete) a variable, use the command \unset. To show the values of all variables, call \set without any argument.

Note

The arguments of \set are subject to the same substitution rules as with other commands. Thus you can construct interesting references such as \set :foo 'something' and get soft links or variable variables of Perl or PHP fame, respectively. Unfortunately (or fortunately?), there is no way to do anything useful with these constructs. On the other hand, \set bar :foo is a perfectly valid way to copy a variable.

A number of these variables are treated specially by psql. They represent certain option settings that can be changed at run time by altering the value of the variable, or in some cases represent changeable state of psql. By convention, all specially treated variables’ names consist of all upper-case ASCII letters (and possibly digits and underscores). To ensure maximum compatibility in the future, avoid using such variable names for your own purposes.

Variables that control psql‘s behavior generally cannot be unset or set to invalid values. An \unset command is allowed but is interpreted as setting the variable to its default value. A \set command without a second argument is interpreted as setting the variable to on, for control variables that accept that value, and is rejected for others. Also, control variables that accept the values on and off will also accept other common spellings of Boolean values, such as true and false.

The specially treated variables are:

AUTOCOMMIT #

When on (the default), each SQL command is automatically committed upon successful completion. To postpone commit in this mode, you must enter a BEGIN or START TRANSACTION SQL command. When off or unset, SQL commands are not committed until you explicitly issue COMMIT or END. The autocommit-off mode works by issuing an implicit BEGIN for you, just before any command that is not already in a transaction block and is not itself a BEGIN or other transaction-control command, nor a command that cannot be executed inside a transaction block (such as VACUUM).

Note

In autocommit-off mode, you must explicitly abandon any failed transaction by entering ABORT or ROLLBACK. Also keep in mind that if you exit the session without committing, your work will be lost.

Note

The autocommit-on mode is PostgreSQL‘s traditional behavior, but autocommit-off is closer to the SQL spec. If you prefer autocommit-off, you might wish to set it in the system-wide psqlrc file or your ~/.psqlrc file.

COMP_KEYWORD_CASE #

Determines which letter case to use when completing an SQL key word. If set to lower or upper, the completed word will be in lower or upper case, respectively. If set to preserve-lower or preserve-upper (the default), the completed word will be in the case of the word already entered, but words being completed without anything entered will be in lower or upper case, respectively.

DBNAME #

The name of the database you are currently connected to. This is set every time you connect to a database (including program start-up), but can be changed or unset.

ECHO #

If set to all, all nonempty input lines are printed to standard output as they are read. (This does not apply to lines read interactively.) To select this behavior on program start-up, use the switch -a. If set to queries, psql prints each query to standard output as it is sent to the server. The switch to select this behavior is -e. If set to errors, then only failed queries are displayed on standard error output. The switch for this behavior is -b. If set to none (the default), then no queries are displayed.

ECHO_HIDDEN #

When this variable is set to on and a backslash command queries the database, the query is first shown. This feature helps you to study PostgreSQL internals and provide similar functionality in your own programs. (To select this behavior on program start-up, use the switch -E.) If you set this variable to the value noexec, the queries are just shown but are not actually sent to the server and executed. The default value is off.

ENCODING #

The current client character set encoding. This is set every time you connect to a database (including program start-up), and when you change the encoding with \encoding, but it can be changed or unset.

ERROR #

true if the last SQL query failed, false if it succeeded. See also SQLSTATE.

FETCH_COUNT #

If this variable is set to an integer value greater than zero, the results of SELECT queries are fetched and displayed in groups of that many rows, rather than the default behavior of collecting the entire result set before display. Therefore only a limited amount of memory is used, regardless of the size of the result set. Settings of 100 to 1000 are commonly used when enabling this feature. Keep in mind that when using this feature, a query might fail after having already displayed some rows.

Tip

Although you can use any output format with this feature, the default aligned format tends to look bad because each group of FETCH_COUNT rows will be formatted separately, leading to varying column widths across the row groups. The other output formats work better.

HIDE_TABLEAM #

If this variable is set to true, a table’s access method details are not displayed. This is mainly useful for regression tests.

HIDE_TOAST_COMPRESSION #

If this variable is set to true, column compression method details are not displayed. This is mainly useful for regression tests.

HISTCONTROL #

If this variable is set to ignorespace, lines which begin with a space are not entered into the history list. If set to a value of ignoredups, lines matching the previous history line are not entered. A value of ignoreboth combines the two options. If set to none (the default), all lines read in interactive mode are saved on the history list.

Note

This feature was shamelessly plagiarized from Bash.

HISTFILE #

The file name that will be used to store the history list. If unset, the file name is taken from the PSQL_HISTORY environment variable. If that is not set either, the default is ~/.psql_history, or %APPDATA%\postgresql\psql_history on Windows. For example, putting:

\set HISTFILE ~/.psql_history-:DBNAME

in ~/.psqlrc will cause psql to maintain a separate history for each database.

Note

This feature was shamelessly plagiarized from Bash.

HISTSIZE #

The maximum number of commands to store in the command history (default 500). If set to a negative value, no limit is applied.

Note

This feature was shamelessly plagiarized from Bash.

HOST #

The database server host you are currently connected to. This is set every time you connect to a database (including program start-up), but can be changed or unset.

IGNOREEOF #

If set to 1 or less, sending an EOF character (usually Control+D) to an interactive session of psql will terminate the application. If set to a larger numeric value, that many consecutive EOF characters must be typed to make an interactive session terminate. If the variable is set to a non-numeric value, it is interpreted as 10. The default is 0.

Note

This feature was shamelessly plagiarized from Bash.

LASTOID #

The value of the last affected OID, as returned from an INSERT or \lo_import command. This variable is only guaranteed to be valid until after the result of the next SQL command has been displayed. PostgreSQL servers since version 12 do not support OID system columns anymore, thus LASTOID will always be 0 following INSERT when targeting such servers.

LAST_ERROR_MESSAGE
LAST_ERROR_SQLSTATE #

The primary error message and associated SQLSTATE code for the most recent failed query in the current psql session, or an empty string and 00000 if no error has occurred in the current session.

ON_ERROR_ROLLBACK #

When set to on, if a statement in a transaction block generates an error, the error is ignored and the transaction continues. When set to interactive, such errors are only ignored in interactive sessions, and not when reading script files. When set to off (the default), a statement in a transaction block that generates an error aborts the entire transaction. The error rollback mode works by issuing an implicit SAVEPOINT for you, just before each command that is in a transaction block, and then rolling back to the savepoint if the command fails.

ON_ERROR_STOP #

By default, command processing continues after an error. When this variable is set to on, processing will instead stop immediately. In interactive mode, psql will return to the command prompt; otherwise, psql will exit, returning error code 3 to distinguish this case from fatal error conditions, which are reported using error code 1. In either case, any currently running scripts (the top-level script, if any, and any other scripts which it may have in invoked) will be terminated immediately. If the top-level command string contained multiple SQL commands, processing will stop with the current command.

PORT #

The database server port to which you are currently connected. This is set every time you connect to a database (including program start-up), but can be changed or unset.

PROMPT1
PROMPT2
PROMPT3 #

These specify what the prompts psql issues should look like. See Prompting below.

QUIET #

Setting this variable to on is equivalent to the command line option -q. It is probably not too useful in interactive mode.

ROW_COUNT #

The number of rows returned or affected by the last SQL query, or 0 if the query failed or did not report a row count.

SERVER_VERSION_NAME
SERVER_VERSION_NUM #

The server’s version number as a string, for example 9.6.2, 10.1 or 11beta1, and in numeric form, for example 90602 or 100001. These are set every time you connect to a database (including program start-up), but can be changed or unset.

SHELL_ERROR #

true if the last shell command failed, false if it succeeded. This applies to shell commands invoked via the \!, \g, \o, \w, and \copy meta-commands, as well as backquote (`) expansion. Note that for \o, this variable is updated when the output pipe is closed by the next \o command. See also SHELL_EXIT_CODE.

SHELL_EXIT_CODE #

The exit status returned by the last shell command. 0–127 represent program exit codes, 128–255 indicate termination by a signal, and -1 indicates failure to launch a program or to collect its exit status. This applies to shell commands invoked via the \!, \g, \o, \w, and \copy meta-commands, as well as backquote (`) expansion. Note that for \o, this variable is updated when the output pipe is closed by the next \o command. See also SHELL_ERROR.

SHOW_ALL_RESULTS #

When this variable is set to off, only the last result of a combined query (\;) is shown instead of all of them. The default is on. The off behavior is for compatibility with older versions of psql.

SHOW_CONTEXT #

This variable can be set to the values never, errors, or always to control whether CONTEXT fields are displayed in messages from the server. The default is errors (meaning that context will be shown in error messages, but not in notice or warning messages). This setting has no effect when VERBOSITY is set to terse or sqlstate. (See also \errverbose, for use when you want a verbose version of the error you just got.)

SINGLELINE #

Setting this variable to on is equivalent to the command line option -S.

SINGLESTEP #

Setting this variable to on is equivalent to the command line option -s.

SQLSTATE #

The error code (see Appendix A) associated with the last SQL query’s failure, or 00000 if it succeeded.

USER #

The database user you are currently connected as. This is set every time you connect to a database (including program start-up), but can be changed or unset.

VERBOSITY #

This variable can be set to the values default, verbose, terse, or sqlstate to control the verbosity of error reports. (See also \errverbose, for use when you want a verbose version of the error you just got.)

VERSION
VERSION_NAME
VERSION_NUM #

These variables are set at program start-up to reflect psql‘s version, respectively as a verbose string, a short string (e.g., 9.6.2, 10.1, or 11beta1), and a number (e.g., 90602 or 100001). They can be changed or unset.

SQL Interpolation

A key feature of psql variables is that you can substitute (interpolate) them into regular SQL statements, as well as the arguments of meta-commands. Furthermore, psql provides facilities for ensuring that variable values used as SQL literals and identifiers are properly quoted. The syntax for interpolating a value without any quoting is to prepend the variable name with a colon (:). For example,

testdb=> \set foo 'my_table'
testdb=> SELECT * FROM :foo;

would query the table my_table. Note that this may be unsafe: the value of the variable is copied literally, so it can contain unbalanced quotes, or even backslash commands. You must make sure that it makes sense where you put it.

When a value is to be used as an SQL literal or identifier, it is safest to arrange for it to be quoted. To quote the value of a variable as an SQL literal, write a colon followed by the variable name in single quotes. To quote the value as an SQL identifier, write a colon followed by the variable name in double quotes. These constructs deal correctly with quotes and other special characters embedded within the variable value. The previous example would be more safely written this way:

testdb=> \set foo 'my_table'
testdb=> SELECT * FROM :"foo";

Variable interpolation will not be performed within quoted SQL literals and identifiers. Therefore, a construction such as ':foo' doesn’t work to produce a quoted literal from a variable’s value (and it would be unsafe if it did work, since it wouldn’t correctly handle quotes embedded in the value).

One example use of this mechanism is to copy the contents of a file into a table column. First load the file into a variable and then interpolate the variable’s value as a quoted string:

testdb=> \set content `cat my_file.txt`
testdb=> INSERT INTO my_table VALUES (:'content');

(Note that this still won’t work if my_file.txt contains NUL bytes. psql does not support embedded NUL bytes in variable values.)

Since colons can legally appear in SQL commands, an apparent attempt at interpolation (that is, :name, :'name', or :"name") is not replaced unless the named variable is currently set. In any case, you can escape a colon with a backslash to protect it from substitution.

The :{?name} special syntax returns TRUE or FALSE depending on whether the variable exists or not, and is thus always substituted, unless the colon is backslash-escaped.

The colon syntax for variables is standard SQL for embedded query languages, such as ECPG. The colon syntaxes for array slices and type casts are PostgreSQL extensions, which can sometimes conflict with the standard usage. The colon-quote syntax for escaping a variable’s value as an SQL literal or identifier is a psql extension.

Prompting

The prompts psql issues can be customized to your preference. The three variables PROMPT1, PROMPT2, and PROMPT3 contain strings and special escape sequences that describe the appearance of the prompt. Prompt 1 is the normal prompt that is issued when psql requests a new command. Prompt 2 is issued when more input is expected during command entry, for example because the command was not terminated with a semicolon or a quote was not closed. Prompt 3 is issued when you are running an SQL COPY FROM STDIN command and you need to type in a row value on the terminal.

The value of the selected prompt variable is printed literally, except where a percent sign (%) is encountered. Depending on the next character, certain other text is substituted instead. Defined substitutions are:

%M #

The full host name (with domain name) of the database server, or [local] if the connection is over a Unix domain socket, or [local:/dir/name], if the Unix domain socket is not at the compiled in default location.

%m #

The host name of the database server, truncated at the first dot, or [local] if the connection is over a Unix domain socket.

%> #

The port number at which the database server is listening.

%n #

The database session user name. (The expansion of this value might change during a database session as the result of the command SET SESSION AUTHORIZATION.)

%/ #

The name of the current database.

%~ #

Like %/, but the output is ~ (tilde) if the database is your default database.

%# #

If the session user is a database superuser, then a #, otherwise a >. (The expansion of this value might change during a database session as the result of the command SET SESSION AUTHORIZATION.)

%p #

The process ID of the backend currently connected to.

%R #

In prompt 1 normally =, but @ if the session is in an inactive branch of a conditional block, or ^ if in single-line mode, or ! if the session is disconnected from the database (which can happen if \connect fails). In prompt 2 %R is replaced by a character that depends on why psql expects more input: - if the command simply wasn’t terminated yet, but * if there is an unfinished /* ... */ comment, a single quote if there is an unfinished quoted string, a double quote if there is an unfinished quoted identifier, a dollar sign if there is an unfinished dollar-quoted string, or ( if there is an unmatched left parenthesis. In prompt 3 %R doesn’t produce anything.

%x #

Transaction status: an empty string when not in a transaction block, or * when in a transaction block, or ! when in a failed transaction block, or ? when the transaction state is indeterminate (for example, because there is no connection).

%l #

The line number inside the current statement, starting from 1.

%digits #

The character with the indicated octal code is substituted.

%:name: #

The value of the psql variable name. See Variables, above, for details.

%`command` #

The output of command, similar to ordinary back-tick substitution.

%[%] #

Prompts can contain terminal control characters which, for example, change the color, background, or style of the prompt text, or change the title of the terminal window. In order for the line editing features of Readline to work properly, these non-printing control characters must be designated as invisible by surrounding them with %[ and %]. Multiple pairs of these can occur within the prompt. For example:

testdb=> \set PROMPT1 '%[%033[1;33;40m%]%n@%/%R%[%033[0m%]%# '

results in a boldfaced (1;) yellow-on-black (33;40) prompt on VT100-compatible, color-capable terminals.

%w #

Whitespace of the same width as the most recent output of PROMPT1. This can be used as a PROMPT2 setting, so that multi-line statements are aligned with the first line, but there is no visible secondary prompt.

To insert a percent sign into your prompt, write %%. The default prompts are '%/%R%x%# ' for prompts 1 and 2, and '>> ' for prompt 3.

Note

This feature was shamelessly plagiarized from tcsh.

Command-Line Editing

psql uses the Readline or libedit library, if available, for convenient line editing and retrieval. The command history is automatically saved when psql exits and is reloaded when psql starts up. Type up-arrow or control-P to retrieve previous lines.

You can also use tab completion to fill in partially-typed keywords and SQL object names in many (by no means all) contexts. For example, at the start of a command, typing ins and pressing TAB will fill in insert into . Then, typing a few characters of a table or schema name and pressing TAB will fill in the unfinished name, or offer a menu of possible completions when there’s more than one. (Depending on the library in use, you may need to press TAB more than once to get a menu.)

Tab completion for SQL object names requires sending queries to the server to find possible matches. In some contexts this can interfere with other operations. For example, after BEGIN it will be too late to issue SET TRANSACTION ISOLATION LEVEL if a tab-completion query is issued in between. If you do not want tab completion at all, you can turn it off permanently by putting this in a file named .inputrc in your home directory:

$if psql
set disable-completion on
$endif

(This is not a psql but a Readline feature. Read its documentation for further details.)

The -n (--no-readline) command line option can also be useful to disable use of Readline for a single run of psql. This prevents tab completion, use or recording of command line history, and editing of multi-line commands. It is particularly useful when you need to copy-and-paste text that contains TAB characters.

Материал из Кафедра ИУ5 МГТУ им. Н.Э.Баумана — студенческое сообщество

Postgresql logo.png

В статье пойдёт речь о том, как добиться корректного вывода кириллицы в «консоли» Windows (cmd.exe).

Содержание

  • 1 Описание проблемы
  • 2 Решение проблемы
    • 2.1 Суть
    • 2.2 Конкретные действия
      • 2.2.1 Супер быстро и просто
      • 2.2.2 Быстро и просто
      • 2.2.3 Посложнее и подольше

Описание проблемы

В дистрибутив PostgreSQL, помимо всего прочего, для работы с СУБД входит:

  • приложение с графическим интерфейсом pgAdmin;
  • консольная утилита psql.

При работе с psql в среде Windows пользователи всегда довольно часто сталкиваются с проблемой вывода кириллицы. Например, при отображении результатов запроса к таблице, в полях которых хранятся строковые данные на русском языке.

Psql.codepage.fail.png

Ну и зачем тогда работать с psql, кому нужно долбить клавиатурой в консольке, когда можно всё сделать красиво и быстро в pgAdmin? Ну, не всегда pgAdmin доступен, особенно если речь идёт об удалённой машине. Кроме того, выполнение SQL-запросов в текстовом режиме консоли — это +10 к хакирству.

Решение проблемы

Версии ПО:

  • MS Windows 7 SP1 x64;
  • PostgreSQL 8.4.12 x32.

На сервере имеется БД, созданная в кодировке UTF8.

Суть

Суть проблемы в том, что cmd.exe работает (и так будет до скончания времён) в кодировке CP866, а сама Windows — в WIN1251, о чём psql предупреждает при начале работы:

WARNING: Console code page (866) differs from Windows code page (1251)
         8-bit characters might not work correctly. See psql reference
         page "Notes for Windows users" for details.

Значит, надо как-то добиться, чтобы кодировка была одна.

В разных источниках встречаются разные рецепты, включая правку реестра и подмену файлов в системных папках Windows. Ничего этого делать не нужно, достаточно всего трёх шагов:

  1. сменить шрифт у cmd.exe;
  2. сменить текущую кодовую страницу cmd.exe;
  3. сменить кодировку на стороне клиента в psql.

Конкретные действия

Супер быстро и просто

Запускаете cmd.exe, оттуда psql:

psql -d ВАШАБАЗА -U ВАШЛОГИН

Далее:

psql \! chcp 1251

Posgresql console 1251.png

Быстро и просто

Запускаете cmd.exe, оттуда psql:

psql -d ВАШАБАЗА -U ВАШЛОГИН

Вводите пароль (если установлен) и выполняете команду:

set client_encoding='WIN866';

И всё. Теперь результаты запроса, содержащие кириллицу, будут отображаться нормально. Но есть небольшой косяк:

Psql.codepage.866.png

Потому предлагаем ещё способ, который этого недостатка лишён.

Посложнее и подольше

Запустить cmd.exe, нажать мышью в правом левом верхнем углу окна, там Свойства — Шрифт — выбрать Lucida Console. Нажать ОК.

Psql.console.font.png

Выполнить команду:

chcp 1251

В ответ выведет:

Текущая кодовая страница: 1251

Запустить psql;

psql -d ВАШАБАЗА -U ВАШЛОГИН

Кстати, обратите внимание — теперь предупреждения о несовпадении кодировок нет.

Выполнить:

set client_encoding='win1251';

Он выведет:

SET

Всё, теперь кириллица будет нормально отображаться.

Проверяем:

Psql.codepage.ok.png

NAME¶

psql — PostgreSQL interactive terminal

SYNOPSIS¶

psql [option…]
[dbname [username]]

DESCRIPTION¶

psql is a terminal-based front-end to PostgreSQL. It enables you
to type in queries interactively, issue them to PostgreSQL, and see the
query results. Alternatively, input can be from a file or from command line
arguments. In addition, psql provides a number of meta-commands and various
shell-like features to facilitate writing scripts and automating a wide
variety of tasks.

OPTIONS¶

-a

—echo-all

Print all nonempty input lines to standard output as they
are read. (This does not apply to lines read interactively.) This is
equivalent to setting the variable ECHO to all.

-A

—no-align

Switches to unaligned output mode. (The default output
mode is otherwise aligned.) This is equivalent to \pset format
unaligned
.

-b

—echo-errors

Print failed SQL commands to standard error output. This
is equivalent to setting the variable ECHO to errors.

-c command

—command=command

Specifies that psql is to execute the given command
string, command. This option can be repeated and combined in any order
with the -f option. When either -c or -f is specified,
psql does not read commands from standard input; instead it terminates after
processing all the -c and -f options in sequence.

command must be either a command string that is completely
parsable by the server (i.e., it contains no psql-specific features), or a
single backslash command. Thus you cannot mix SQL and psql meta-commands
within a -c option. To achieve that, you could use repeated -c
options or pipe the string into psql, for example:

psql -c '\x' -c 'SELECT * FROM foo;'

or

echo '\x \\ SELECT * FROM foo;' | psql

(\\ is the separator meta-command.)

Each SQL command string passed to -c is sent to the server
as a single query. Because of this, the server executes it as a single
transaction even if the string contains multiple SQL commands, unless there
are explicit BEGIN/COMMIT commands included in the string to
divide it into multiple transactions. Also, psql only prints the result of
the last SQL command in the string. This is different from the behavior when
the same string is read from a file or fed to psql’s standard input, because
then psql sends each SQL command separately.

Because of this behavior, putting more than one command in a
single -c string often has unexpected results. It’s better to use
repeated -c commands or feed multiple commands to psql’s standard
input, either using echo as illustrated above, or via a shell here-document,
for example:

psql <<EOF
\x
SELECT * FROM foo;
EOF

-d dbname

—dbname=dbname

Specifies the name of the database to connect to. This is
equivalent to specifying dbname as the first non-option argument on the
command line.

If this parameter contains an = sign or starts with a valid URI
prefix (postgresql:// or postgres://), it is treated as a conninfo
string. See Section 33.1.1 for more information.

-e

—echo-queries

Copy all SQL commands sent to the server to standard
output as well. This is equivalent to setting the variable ECHO to
queries.

-E

—echo-hidden

Echo the actual queries generated by \d and other
backslash commands. You can use this to study psql’s internal operations. This
is equivalent to setting the variable ECHO_HIDDEN to on.

-f filename

—file=filename

Read commands from the file filename, rather than
standard input. This option can be repeated and combined in any order with the
-c option. When either -c or -f is specified, psql does
not read commands from standard input; instead it terminates after processing
all the -c and -f options in sequence. Except for that, this
option is largely equivalent to the meta-command \i.

If filename is — (hyphen), then standard input is read
until an EOF indication or \q meta-command. This can be used to
intersperse interactive input with input from files. Note however that
Readline is not used in this case (much as if -n had been
specified).

Using this option is subtly different from writing psql <
filename. In general, both will do what you expect, but using -f
enables some nice features such as error messages with line numbers. There
is also a slight chance that using this option will reduce the start-up
overhead. On the other hand, the variant using the shell’s input redirection
is (in theory) guaranteed to yield exactly the same output you would have
received had you entered everything by hand.

-F separator

—field-separator=separator

Use separator as the field separator for unaligned
output. This is equivalent to \pset fieldsep or \f.

-h hostname

—host=hostname

Specifies the host name of the machine on which the
server is running. If the value begins with a slash, it is used as the
directory for the Unix-domain socket.

-H

—html

Turn on HTML tabular output. This is equivalent to \pset
format html or the \H command.

-l

—list

List all available databases, then exit. Other
non-connection options are ignored. This is similar to the meta-command
\list.

When this option is used, psql will connect to the database
postgres, unless a different database is named on the command line (option
-d or non-option argument, possibly via a service entry, but not via
an environment variable).

-L filename

—log-file=filename

Write all query output into file filename, in
addition to the normal output destination.

-n

—no-readline

Do not use Readline for line editing and do not use the
command history. This can be useful to turn off tab expansion when cutting and
pasting.

-o filename

—output=filename

Put all query output into file filename. This is
equivalent to the command \o.

-p port

—port=port

Specifies the TCP port or the local Unix-domain socket
file extension on which the server is listening for connections. Defaults to
the value of the PGPORT environment variable or, if not set, to the
port specified at compile time, usually 5432.

-P assignment

—pset=assignment

Specifies printing options, in the style of \pset.
Note that here you have to separate name and value with an equal sign instead
of a space. For example, to set the output format to LaTeX, you could write -P
format=latex.

-q

—quiet

Specifies that psql should do its work quietly. By
default, it prints welcome messages and various informational output. If this
option is used, none of this happens. This is useful with the -c
option. This is equivalent to setting the variable QUIET to on.

-R separator

—record-separator=separator

Use separator as the record separator for
unaligned output. This is equivalent to \pset recordsep.

-s

—single-step

Run in single-step mode. That means the user is prompted
before each command is sent to the server, with the option to cancel execution
as well. Use this to debug scripts.

-S

—single-line

Runs in single-line mode where a newline terminates an
SQL command, as a semicolon does.

Note

This mode is provided for those who insist on it, but you are not necessarily
encouraged to use it. In particular, if you mix SQL and meta-commands on a
line the order of execution might not always be clear to the inexperienced
user.

-t

—tuples-only

Turn off printing of column names and result row count
footers, etc. This is equivalent to \t or \pset
tuples_only
.

-T table_options

—table-attr=table_options

Specifies options to be placed within the HTML table tag.
See \pset tableattr for details.

-U username

—username=username

Connect to the database as the user username
instead of the default. (You must have permission to do so, of course.)

-v assignment

—set=assignment

—variable=assignment

Perform a variable assignment, like the \set
meta-command. Note that you must separate name and value, if any, by an equal
sign on the command line. To unset a variable, leave off the equal sign. To
set a variable with an empty value, use the equal sign but leave off the
value. These assignments are done during command line processing, so variables
that reflect connection state will get overwritten later.

-V

—version

Print the psql version and exit.

-w

—no-password

Never issue a password prompt. If the server requires
password authentication and a password is not available by other means such as
a .pgpass file, the connection attempt will fail. This option can be useful in
batch jobs and scripts where no user is present to enter a password.

Note that this option will remain set for the entire session, and
so it affects uses of the meta-command \connect as well as the
initial connection attempt.

-W

—password

Force psql to prompt for a password before connecting to
a database.

This option is never essential, since psql will automatically
prompt for a password if the server demands password authentication.
However, psql will waste a connection attempt finding out that the server
wants a password. In some cases it is worth typing -W to avoid the
extra connection attempt.

Note that this option will remain set for the entire session, and
so it affects uses of the meta-command \connect as well as the
initial connection attempt.

-x

—expanded

Turn on the expanded table formatting mode. This is
equivalent to \x or \pset expanded.

-X,

—no-psqlrc

Do not read the start-up file (neither the system-wide
psqlrc file nor the user’s ~/.psqlrc file).

-z

—field-separator-zero

Set the field separator for unaligned output to a zero
byte. This is equivalent to \pset fieldsep_zero.

-0

—record-separator-zero

Set the record separator for unaligned output to a zero
byte. This is useful for interfacing, for example, with xargs -0. This is
equivalent to \pset recordsep_zero.

-1

—single-transaction

This option can only be used in combination with one or
more -c and/or -f options. It causes psql to issue a
BEGIN command before the first such option and a COMMIT command
after the last one, thereby wrapping all the commands into a single
transaction. This ensures that either all the commands complete successfully,
or no changes are applied.

If the commands themselves contain BEGIN, COMMIT, or
ROLLBACK, this option will not have the desired effects. Also, if an
individual command cannot be executed inside a transaction block, specifying
this option will cause the whole transaction to fail.

-?

—help[=topic]

Show help about psql and exit. The optional topic
parameter (defaulting to options) selects which part of psql is explained:
commands describes psql’s backslash commands; options describes the
command-line options that can be passed to psql; and variables shows help
about psql configuration variables.

EXIT STATUS¶

psql returns 0 to the shell if it finished normally, 1 if a fatal
error of its own occurs (e.g. out of memory, file not found), 2 if the
connection to the server went bad and the session was not interactive, and 3
if an error occurred in a script and the variable ON_ERROR_STOP was
set.

USAGE¶

Connecting to a Database¶

psql is a regular PostgreSQL client application. In order to
connect to a database you need to know the name of your target database, the
host name and port number of the server, and what user name you want to
connect as. psql can be told about those parameters via command line
options, namely -d, -h, -p, and -U respectively.
If an argument is found that does not belong to any option it will be
interpreted as the database name (or the user name, if the database name is
already given). Not all of these options are required; there are useful
defaults. If you omit the host name, psql will connect via a Unix-domain
socket to a server on the local host, or via TCP/IP to localhost on machines
that don’t have Unix-domain sockets. The default port number is determined
at compile time. Since the database server uses the same default, you will
not have to specify the port in most cases. The default user name is your
operating-system user name, as is the default database name. Note that you
cannot just connect to any database under any user name. Your database
administrator should have informed you about your access rights.

When the defaults aren’t quite right, you can save yourself some
typing by setting the environment variables PGDATABASE,
PGHOST, PGPORT and/or PGUSER to appropriate values.
(For additional environment variables, see Section 33.14.) It is also
convenient to have a ~/.pgpass file to avoid regularly having to type in
passwords. See Section 33.15 for more information.

An alternative way to specify connection parameters is in a
conninfo string or a URI, which is used instead of a database name.
This mechanism give you very wide control over the connection. For
example:

This way you can also use LDAP for connection parameter lookup as
described in Section 33.17. See Section 33.1.2 for more
information on all the available connection options.

If the connection could not be made for any reason (e.g.,
insufficient privileges, server is not running on the targeted host, etc.),
psql will return an error and terminate.

If both standard input and standard output are a terminal, then
psql sets the client encoding to “auto”, which will detect the
appropriate client encoding from the locale settings (LC_CTYPE
environment variable on Unix systems). If this doesn’t work out as expected,
the client encoding can be overridden using the environment variable
PGCLIENTENCODING.

Entering SQL Commands¶

In normal operation, psql provides a prompt with the name of the
database to which psql is currently connected, followed by the string =>.
For example:

$ psql testdb
psql (10.5)
Type "help" for help.
testdb=>

At the prompt, the user can type in SQL commands. Ordinarily,
input lines are sent to the server when a command-terminating semicolon is
reached. An end of line does not terminate a command. Thus commands can be
spread over several lines for clarity. If the command was sent and executed
without error, the results of the command are displayed on the screen.

If untrusted users have access to a database that has not adopted
a secure schema usage pattern, begin your session by removing
publicly-writable schemas from search_path. One can add
options=-csearch_path= to the connection string or issue SELECT
pg_catalog.set_config(‘search_path’, », false) before other SQL commands.
This consideration is not specific to psql; it applies to every interface
for executing arbitrary SQL commands.

Whenever a command is executed, psql also polls for asynchronous
notification events generated by LISTEN(7) and NOTIFY(7).

While C-style block comments are passed to the server for
processing and removal, SQL-standard comments are removed by psql.

Anything you enter in psql that begins with an unquoted backslash
is a psql meta-command that is processed by psql itself. These commands make
psql more useful for administration or scripting. Meta-commands are often
called slash or backslash commands.

The format of a psql command is the backslash, followed
immediately by a command verb, then any arguments. The arguments are
separated from the command verb and each other by any number of whitespace
characters.

To include whitespace in an argument you can quote it with single
quotes. To include a single quote in an argument, write two single quotes
within single-quoted text. Anything contained in single quotes is
furthermore subject to C-like substitutions for \n (new line), \t (tab), \b
(backspace), \r (carriage return), \f (form feed), \digits (octal),
and \xdigits (hexadecimal). A backslash preceding any other character
within single-quoted text quotes that single character, whatever it is.

If an unquoted colon (:) followed by a psql variable name appears
within an argument, it is replaced by the variable’s value, as described in
SQL Interpolation. The forms :’variable_name‘ and
variable_name» described there work as well.

Within an argument, text that is enclosed in backquotes (`) is
taken as a command line that is passed to the shell. The output of the
command (with any trailing newline removed) replaces the backquoted text.
Within the text enclosed in backquotes, no special quoting or other
processing occurs, except that appearances of :variable_name where
variable_name is a psql variable name are replaced by the variable’s
value. Also, appearances of :’variable_name‘ are replaced by the
variable’s value suitably quoted to become a single shell command argument.
(The latter form is almost always preferable, unless you are very sure of
what is in the variable.) Because carriage return and line feed characters
cannot be safely quoted on all platforms, the :’variable_name‘ form
prints an error message and does not substitute the variable value when such
characters appear in the value.

Some commands take an SQL identifier (such as a table name) as
argument. These arguments follow the syntax rules of SQL: Unquoted letters
are forced to lowercase, while double quotes («) protect letters from
case conversion and allow incorporation of whitespace into the identifier.
Within double quotes, paired double quotes reduce to a single double quote
in the resulting name. For example, FOO»BAR»BAZ is interpreted as
fooBARbaz, and «A weird»» name» becomes A weird»
name.

Parsing for arguments stops at the end of the line, or when
another unquoted backslash is found. An unquoted backslash is taken as the
beginning of a new meta-command. The special sequence \\ (two backslashes)
marks the end of arguments and continues parsing SQL commands, if any. That
way SQL and psql commands can be freely mixed on a line. But in any case,
the arguments of a meta-command cannot continue beyond the end of the
line.

Many of the meta-commands act on the current query buffer. This is
simply a buffer holding whatever SQL command text has been typed but not yet
sent to the server for execution. This will include previous input lines as
well as any text appearing before the meta-command on the same line.

The following meta-commands are defined:

\a

If the current table output format is unaligned, it is
switched to aligned. If it is not unaligned, it is set to unaligned. This
command is kept for backwards compatibility. See \pset for a more
general solution.

\c or \connect [ -reuse-previous=on|off ] [ dbname [
username ] [ host ] [ port ] | conninfo ]

Establishes a new connection to a PostgreSQL server. The
connection parameters to use can be specified either using a positional
syntax, or using conninfo connection strings as detailed in
Section 33.1.1.

Where the command omits database name, user, host, or port, the
new connection can reuse values from the previous connection. By default,
values from the previous connection are reused except when processing a
conninfo string. Passing a first argument of -reuse-previous=on or
-reuse-previous=off overrides that default. When the command neither
specifies nor reuses a particular parameter, the libpq default is used.
Specifying any of dbname, username, host or port
as — is equivalent to omitting that parameter.

If the new connection is successfully made, the previous
connection is closed. If the connection attempt failed (wrong user name,
access denied, etc.), the previous connection will only be kept if psql is
in interactive mode. When executing a non-interactive script, processing
will immediately stop with an error. This distinction was chosen as a user
convenience against typos on the one hand, and a safety mechanism that
scripts are not accidentally acting on the wrong database on the other
hand.

Examples:

\C [ title ]

Sets the title of any tables being printed as the result
of a query or unset any such title. This command is equivalent to \pset title
title. (The name of this command derives from “caption”,
as it was previously only used to set the caption in an HTML table.)

\cd [ directory ]

Changes the current working directory to
directory. Without argument, changes to the current user’s home
directory.

Tip

To print your current working directory, use \! pwd.

\conninfo

Outputs information about the current database
connection.

\copy { table [ ( column_list ) ] | ( query )
} { from | to } { ‘filename’ | program ‘command’ | stdin |
stdout | pstdin | pstdout } [ [ with ] ( option [, …] ) ]

Performs a frontend (client) copy. This is an operation
that runs an SQL COPY(7) command, but instead of the server reading or
writing the specified file, psql reads or writes the file and routes the data
between the server and the local file system. This means that file
accessibility and privileges are those of the local user, not the server, and
no SQL superuser privileges are required.

When program is specified, command is executed by psql and
the data passed from or to command is routed between the server and
the client. Again, the execution privileges are those of the local user, not
the server, and no SQL superuser privileges are required.

For \copy … from stdin, data rows are read from the same source
that issued the command, continuing until \. is read or the stream reaches
EOF. This option is useful for populating tables in-line within a SQL script
file. For \copy … to stdout, output is sent to the same place as psql
command output, and the COPY count command status is not printed
(since it might be confused with a data row). To read/write psql’s standard
input or output regardless of the current command source or \o option, write
from pstdin or to pstdout.

The syntax of this command is similar to that of the SQL
COPY(7) command. All options other than the data source/destination
are as specified for COPY(7). Because of this, special parsing rules
apply to the \copy meta-command. Unlike most other meta-commands, the
entire remainder of the line is always taken to be the arguments of
\copy, and neither variable interpolation nor backquote expansion are
performed in the arguments.

Tip

This operation is not as efficient as the SQL COPY command because all
data must pass through the client/server connection. For large amounts of data
the SQL command might be preferable.

\copyright

Shows the copyright and distribution terms of
PostgreSQL.

\crosstabview [ colV [ colH [ colD [
sortcolH ] ] ] ]

Executes the current query buffer (like \g) and shows the
results in a crosstab grid. The query must return at least three columns. The
output column identified by colV becomes a vertical header and the
output column identified by colH becomes a horizontal header.
colD identifies the output column to display within the grid.
sortcolH identifies an optional sort column for the horizontal header.

Each column specification can be a column number (starting at 1)
or a column name. The usual SQL case folding and quoting rules apply to
column names. If omitted, colV is taken as column 1 and colH
as column 2. colH must differ from colV. If colD is not
specified, then there must be exactly three columns in the query result, and
the column that is neither colV nor colH is taken to be
colD.

The vertical header, displayed as the leftmost column, contains
the values found in column colV, in the same order as in the query
results, but with duplicates removed.

The horizontal header, displayed as the first row, contains the
values found in column colH, with duplicates removed. By default,
these appear in the same order as in the query results. But if the optional
sortcolH argument is given, it identifies a column whose values must
be integer numbers, and the values from colH will appear in the
horizontal header sorted according to the corresponding sortcolH
values.

Inside the crosstab grid, for each distinct value x of colH
and each distinct value y of colV, the cell located at the
intersection (x,y) contains the value of the colD column in the query result
row for which the value of colH is x and the value of colV is
y. If there is no such row, the cell is empty. If there are multiple such
rows, an error is reported.

\d[S+] [ pattern ]

For each relation (table, view, materialized view, index,
sequence, or foreign table) or composite type matching the pattern,
show all columns, their types, the tablespace (if not the default) and any
special attributes such as NOT NULL or defaults. Associated indexes,
constraints, rules, and triggers are also shown. For foreign tables, the
associated foreign server is shown as well. (“Matching the
pattern” is defined in Patterns below.)

For some types of relation, \d shows additional information for
each column: column values for sequences, indexed expressions for indexes,
and foreign data wrapper options for foreign tables.

The command form \d+ is identical, except that more information is
displayed: any comments associated with the columns of the table are shown,
as is the presence of OIDs in the table, the view definition if the relation
is a view, a non-default replica identity setting.

By default, only user-created objects are shown; supply a pattern
or the S modifier to include system objects.

Note

If \d is used without a pattern argument, it is equivalent to
\dtvmsE which will show a list of all visible tables, views,
materialized views, sequences and foreign tables. This is purely a convenience
measure.

\da[S] [ pattern ]

Lists aggregate functions, together with their return
type and the data types they operate on. If pattern is specified, only
aggregates whose names match the pattern are shown. By default, only
user-created objects are shown; supply a pattern or the S modifier to include
system objects.

\dA[+] [ pattern ]

Lists access methods. If pattern is specified,
only access methods whose names match the pattern are shown. If + is appended
to the command name, each access method is listed with its associated handler
function and description.

\db[+] [ pattern ]

Lists tablespaces. If pattern is specified, only
tablespaces whose names match the pattern are shown. If + is appended to the
command name, each tablespace is listed with its associated options, on-disk
size, permissions and description.

\dc[S+] [ pattern ]

Lists conversions between character-set encodings. If
pattern is specified, only conversions whose names match the pattern
are listed. By default, only user-created objects are shown; supply a pattern
or the S modifier to include system objects. If + is appended to the command
name, each object is listed with its associated description.

\dC[+] [ pattern ]

Lists type casts. If pattern is specified, only
casts whose source or target types match the pattern are listed. If + is
appended to the command name, each object is listed with its associated
description.

\dd[S] [ pattern ]

Shows the descriptions of objects of type constraint,
operator class, operator family, rule, and trigger. All other comments may be
viewed by the respective backslash commands for those object types.

\dd displays descriptions for objects matching the pattern,
or of visible objects of the appropriate type if no argument is given. But
in either case, only objects that have a description are listed. By default,
only user-created objects are shown; supply a pattern or the S modifier to
include system objects.

Descriptions for objects can be created with the COMMENT(7)
SQL command.

\dD[S+] [ pattern ]

Lists domains. If pattern is specified, only
domains whose names match the pattern are shown. By default, only user-created
objects are shown; supply a pattern or the S modifier to include system
objects. If + is appended to the command name, each object is listed with its
associated permissions and description.

\ddp [ pattern ]

Lists default access privilege settings. An entry is
shown for each role (and schema, if applicable) for which the default
privilege settings have been changed from the built-in defaults. If
pattern is specified, only entries whose role name or schema name
matches the pattern are listed.

The ALTER DEFAULT PRIVILEGES (ALTER_DEFAULT_PRIVILEGES(7))
command is used to set default access privileges. The meaning of the
privilege display is explained under GRANT(7).

\dE[S+] [ pattern ]

\di[S+] [ pattern ]

\dm[S+] [ pattern ]

\ds[S+] [ pattern ]

\dt[S+] [ pattern ]

\dv[S+] [ pattern ]

In this group of commands, the letters E, i, m, s, t, and
v stand for foreign table, index, materialized view, sequence, table, and
view, respectively. You can specify any or all of these letters, in any order,
to obtain a listing of objects of these types. For example, \dit lists indexes
and tables. If + is appended to the command name, each object is listed with
its physical size on disk and its associated description, if any. If
pattern is specified, only objects whose names match the pattern are
listed. By default, only user-created objects are shown; supply a pattern or
the S modifier to include system objects.

\des[+] [ pattern ]

Lists foreign servers (mnemonic: “external
servers”). If pattern is specified, only those servers whose
name matches the pattern are listed. If the form \des+ is used, a full
description of each server is shown, including the server’s ACL, type,
version, options, and description.

\det[+] [ pattern ]

Lists foreign tables (mnemonic: “external
tables”). If pattern is specified, only entries whose table name
or schema name matches the pattern are listed. If the form \det+ is used,
generic options and the foreign table description are also displayed.

\deu[+] [ pattern ]

Lists user mappings (mnemonic: “external
users”). If pattern is specified, only those mappings whose user
names match the pattern are listed. If the form \deu+ is used, additional
information about each mapping is shown.

Caution

\deu+ might also display the user name and password of the remote user, so care
should be taken not to disclose them.

\dew[+] [ pattern ]

Lists foreign-data wrappers (mnemonic: “external
wrappers”). If pattern is specified, only those foreign-data
wrappers whose name matches the pattern are listed. If the form \dew+ is used,
the ACL, options, and description of the foreign-data wrapper are also
shown.

\df[antwS+] [ pattern ]

Lists functions, together with their result data types,
argument data types, and function types, which are classified as
“agg” (aggregate), “normal”,
“trigger”, or “window”. To display only functions
of specific type(s), add the corresponding letters a, n, t, or w to the
command. If pattern is specified, only functions whose names match the
pattern are shown. By default, only user-created objects are shown; supply a
pattern or the S modifier to include system objects. If the form \df+ is used,
additional information about each function is shown, including volatility,
parallel safety, owner, security classification, access privileges, language,
source code and description.

Tip

To look up functions taking arguments or returning values of a specific data
type, use your pager’s search capability to scroll through the \df output.

\dF[+] [ pattern ]

Lists text search configurations. If pattern is
specified, only configurations whose names match the pattern are shown. If the
form \dF+ is used, a full description of each configuration is shown,
including the underlying text search parser and the dictionary list for each
parser token type.

\dFd[+] [ pattern ]

Lists text search dictionaries. If pattern is
specified, only dictionaries whose names match the pattern are shown. If the
form \dFd+ is used, additional information is shown about each selected
dictionary, including the underlying text search template and the option
values.

\dFp[+] [ pattern ]

Lists text search parsers. If pattern is
specified, only parsers whose names match the pattern are shown. If the form
\dFp+ is used, a full description of each parser is shown, including the
underlying functions and the list of recognized token types.

\dFt[+] [ pattern ]

Lists text search templates. If pattern is
specified, only templates whose names match the pattern are shown. If the form
\dFt+ is used, additional information is shown about each template, including
the underlying function names.

\dg[S+] [ pattern ]

Lists database roles. (Since the concepts of
“users” and “groups” have been unified into
“roles”, this command is now equivalent to \du.) By default,
only user-created roles are shown; supply the S modifier to include system
roles. If pattern is specified, only those roles whose names match the
pattern are listed. If the form \dg+ is used, additional information is shown
about each role; currently this adds the comment for each role.

\dl

This is an alias for \lo_list, which shows a list
of large objects.

\dL[S+] [ pattern ]

Lists procedural languages. If pattern is
specified, only languages whose names match the pattern are listed. By
default, only user-created languages are shown; supply the S modifier to
include system objects. If + is appended to the command name, each language is
listed with its call handler, validator, access privileges, and whether it is
a system object.

\dn[S+] [ pattern ]

Lists schemas (namespaces). If pattern is
specified, only schemas whose names match the pattern are listed. By default,
only user-created objects are shown; supply a pattern or the S modifier to
include system objects. If + is appended to the command name, each object is
listed with its associated permissions and description, if any.

\do[S+] [ pattern ]

Lists operators with their operand and result types. If
pattern is specified, only operators whose names match the pattern are
listed. By default, only user-created objects are shown; supply a pattern or
the S modifier to include system objects. If + is appended to the command
name, additional information about each operator is shown, currently just the
name of the underlying function.

\dO[S+] [ pattern ]

Lists collations. If pattern is specified, only
collations whose names match the pattern are listed. By default, only
user-created objects are shown; supply a pattern or the S modifier to include
system objects. If + is appended to the command name, each collation is listed
with its associated description, if any. Note that only collations usable with
the current database’s encoding are shown, so the results may vary in
different databases of the same installation.

\dp [ pattern ]

Lists tables, views and sequences with their associated
access privileges. If pattern is specified, only tables, views and
sequences whose names match the pattern are listed.

The GRANT(7) and REVOKE(7) commands are used to set
access privileges. The meaning of the privilege display is explained under
GRANT(7).

\drds [ role-pattern [ database-pattern ] ]

Lists defined configuration settings. These settings can
be role-specific, database-specific, or both. role-pattern and
database-pattern are used to select specific roles and databases to
list, respectively. If omitted, or if * is specified, all settings are listed,
including those not role-specific or database-specific, respectively.

The ALTER ROLE (ALTER_ROLE(7)) and ALTER DATABASE
(ALTER_DATABASE(7)) commands are used to define per-role and
per-database configuration settings.

\dRp[+] [ pattern ]

Lists replication publications. If pattern is
specified, only those publications whose names match the pattern are listed.
If + is appended to the command name, the tables associated with each
publication are shown as well.

\dRs[+] [ pattern ]

Lists replication subscriptions. If pattern is
specified, only those subscriptions whose names match the pattern are listed.
If + is appended to the command name, additional properties of the
subscriptions are shown.

\dT[S+] [ pattern ]

Lists data types. If pattern is specified, only
types whose names match the pattern are listed. If + is appended to the
command name, each type is listed with its internal name and size, its allowed
values if it is an enum type, and its associated permissions. By default, only
user-created objects are shown; supply a pattern or the S modifier to include
system objects.

\du[S+] [ pattern ]

Lists database roles. (Since the concepts of
“users” and “groups” have been unified into
“roles”, this command is now equivalent to \dg.) By default,
only user-created roles are shown; supply the S modifier to include system
roles. If pattern is specified, only those roles whose names match the
pattern are listed. If the form \du+ is used, additional information is shown
about each role; currently this adds the comment for each role.

\dx[+] [ pattern ]

Lists installed extensions. If pattern is
specified, only those extensions whose names match the pattern are listed. If
the form \dx+ is used, all the objects belonging to each matching extension
are listed.

\dy[+] [ pattern ]

Lists event triggers. If pattern is specified,
only those event triggers whose names match the pattern are listed. If + is
appended to the command name, each object is listed with its associated
description.

\e or \edit [ filename ] [ line_number ]

If filename is specified, the file is edited;
after the editor exits, the file’s content is copied into the current query
buffer. If no filename is given, the current query buffer is copied to
a temporary file which is then edited in the same fashion. Or, if the current
query buffer is empty, the most recently executed query is copied to a
temporary file and edited in the same fashion.

The new contents of the query buffer are then re-parsed according
to the normal rules of psql, treating the whole buffer as a single line. Any
complete queries are immediately executed; that is, if the query buffer
contains or ends with a semicolon, everything up to that point is executed.
Whatever remains will wait in the query buffer; type semicolon or \g to send
it, or \r to cancel it by clearing the query buffer. Treating the buffer as
a single line primarily affects meta-commands: whatever is in the buffer
after a meta-command will be taken as argument(s) to the meta-command, even
if it spans multiple lines. (Thus you cannot make meta-command-using scripts
this way. Use \i for that.)

If a line number is specified, psql will position the cursor on
the specified line of the file or query buffer. Note that if a single
all-digits argument is given, psql assumes it is a line number, not a file
name.

Tip

See under ENVIRONMENT for how to configure and customize your editor.

\echo text [ … ]

Prints the arguments to the standard output, separated by
one space and followed by a newline. This can be useful to intersperse
information in the output of scripts. For example:

=> \echo `date`
Tue Oct 26 21:40:57 CEST 1999

If the first argument is an unquoted -n the trailing newline is
not written.

Tip

If you use the \o command to redirect your query output you might wish to
use \qecho instead of this command.

\ef [ function_description [ line_number ] ]

This command fetches and edits the definition of the
named function, in the form of a CREATE OR REPLACE FUNCTION command.
Editing is done in the same way as for \edit. After the editor exits, the
updated command waits in the query buffer; type semicolon or \g to send it, or
\r to cancel.

The target function can be specified by name alone, or by name and
arguments, for example foo(integer, text). The argument types must be given
if there is more than one function of the same name.

If no function is specified, a blank CREATE FUNCTION
template is presented for editing.

If a line number is specified, psql will position the cursor on
the specified line of the function body. (Note that the function body
typically does not begin on the first line of the file.)

Unlike most other meta-commands, the entire remainder of the line
is always taken to be the argument(s) of \ef, and neither variable
interpolation nor backquote expansion are performed in the arguments.

Tip

See under ENVIRONMENT for how to configure and customize your editor.

\encoding [ encoding ]

Sets the client character set encoding. Without an
argument, this command shows the current encoding.

\errverbose

Repeats the most recent server error message at maximum
verbosity, as though VERBOSITY were set to verbose and
SHOW_CONTEXT were set to always.

\ev [ view_name [ line_number ] ]

This command fetches and edits the definition of the
named view, in the form of a CREATE OR REPLACE VIEW command. Editing is
done in the same way as for \edit. After the editor exits, the updated command
waits in the query buffer; type semicolon or \g to send it, or \r to cancel.

If no view is specified, a blank CREATE VIEW template is
presented for editing.

If a line number is specified, psql will position the cursor on
the specified line of the view definition.

Unlike most other meta-commands, the entire remainder of the line
is always taken to be the argument(s) of \ev, and neither variable
interpolation nor backquote expansion are performed in the arguments.

\f [ string ]

Sets the field separator for unaligned query output. The
default is the vertical bar (|). It is equivalent to \pset
fieldsep
.

\g [ filename ]

\g [ |command ]

Sends the current query buffer to the server for
execution. If an argument is given, the query’s output is written to the named
file or piped to the given shell command, instead of displaying it as usual.
The file or command is written to only if the query successfully returns zero
or more tuples, not if the query fails or is a non-data-returning SQL command.

If the current query buffer is empty, the most recently sent query
is re-executed instead. Except for that behavior, \g without an argument is
essentially equivalent to a semicolon. A \g with argument is a
“one-shot” alternative to the \o command.

If the argument begins with |, then the entire remainder of the
line is taken to be the command to execute, and neither variable
interpolation nor backquote expansion are performed in it. The rest of the
line is simply passed literally to the shell.

\gexec

Sends the current query buffer to the server, then treats
each column of each row of the query’s output (if any) as a SQL statement to
be executed. For example, to create an index on each column of my_table:

=> SELECT format('create index on my_table(%I)', attname)
-> FROM pg_attribute
-> WHERE attrelid = 'my_table'::regclass AND attnum > 0
-> ORDER BY attnum
-> \gexec
CREATE INDEX
CREATE INDEX
CREATE INDEX
CREATE INDEX

The generated queries are executed in the order in which the rows
are returned, and left-to-right within each row if there is more than one
column. NULL fields are ignored. The generated queries are sent literally to
the server for processing, so they cannot be psql meta-commands nor contain
psql variable references. If any individual query fails, execution of the
remaining queries continues unless ON_ERROR_STOP is set. Execution of
each query is subject to ECHO processing. (Setting ECHO to all
or queries is often advisable when using \gexec.) Query logging,
single-step mode, timing, and other query execution features apply to each
generated query as well.

If the current query buffer is empty, the most recently sent query
is re-executed instead.

\gset [ prefix ]

Sends the current query buffer to the server and stores
the query’s output into psql variables (see Variables). The query to be
executed must return exactly one row. Each column of the row is stored into a
separate variable, named the same as the column. For example:

=> SELECT 'hello' AS var1, 10 AS var2
-> \gset
=> \echo :var1 :var2
hello 10

If you specify a prefix, that string is prepended to the
query’s column names to create the variable names to use:

=> SELECT 'hello' AS var1, 10 AS var2
-> \gset result_
=> \echo :result_var1 :result_var2
hello 10

If a column result is NULL, the corresponding variable is unset
rather than being set.

If the query fails or does not return one row, no variables are
changed.

If the current query buffer is empty, the most recently sent query
is re-executed instead.

\gx [ filename ]

\gx [ |command ]

\gx is equivalent to \g, but forces expanded output mode
for this query. See \x.

\h or \help [ command ]

Gives syntax help on the specified SQL command. If
command is not specified, then psql will list all the commands for
which syntax help is available. If command is an asterisk (*), then
syntax help on all SQL commands is shown.

Unlike most other meta-commands, the entire remainder of the line
is always taken to be the argument(s) of \help, and neither variable
interpolation nor backquote expansion are performed in the arguments.

Note

To simplify typing, commands that consists of several words do not have to be
quoted. Thus it is fine to type \help alter table.

\H or \html

Turns on HTML query output format. If the HTML format is
already on, it is switched back to the default aligned text format. This
command is for compatibility and convenience, but see \pset about
setting other output options.

\i or \include filename

Reads input from the file filename and executes it
as though it had been typed on the keyboard.

If filename is — (hyphen), then standard input is read
until an EOF indication or \q meta-command. This can be used to
intersperse interactive input with input from files. Note that Readline
behavior will be used only if it is active at the outermost level.

Note

If you want to see the lines on the screen as they are read you must set the
variable ECHO to all.

\if expression

\elif expression

\else

\endif

This group of commands implements nestable conditional
blocks. A conditional block must begin with an \if and end with an
\endif. In between there may be any number of \elif clauses,
which may optionally be followed by a single \else clause. Ordinary
queries and other types of backslash commands may (and usually do) appear
between the commands forming a conditional block.

The \if and \elif commands read their argument(s)
and evaluate them as a boolean expression. If the expression yields true
then processing continues normally; otherwise, lines are skipped until a
matching \elif, \else, or \endif is reached. Once an
\if or \elif test has succeeded, the arguments of later
\elif commands in the same block are not evaluated but are treated as
false. Lines following an \else are processed only if no earlier
matching \if or \elif succeeded.

The expression argument of an \if or \elif
command is subject to variable interpolation and backquote expansion, just
like any other backslash command argument. After that it is evaluated like
the value of an on/off option variable. So a valid value is any unambiguous
case-insensitive match for one of: true, false, 1, 0, on, off, yes, no. For
example, t, T, and tR will all be considered to be true.

Expressions that do not properly evaluate to true or false will
generate a warning and be treated as false.

Lines being skipped are parsed normally to identify queries and
backslash commands, but queries are not sent to the server, and backslash
commands other than conditionals (\if, \elif, \else,
\endif) are ignored. Conditional commands are checked only for valid
nesting. Variable references in skipped lines are not expanded, and
backquote expansion is not performed either.

All the backslash commands of a given conditional block must
appear in the same source file. If EOF is reached on the main input file or
an \include-ed file before all local \if-blocks have been
closed, then psql will raise an error.

Here is an example:

-- check for the existence of two separate records in the database and store
-- the results in separate psql variables
SELECT

EXISTS(SELECT 1 FROM customer WHERE customer_id = 123) as is_customer,
EXISTS(SELECT 1 FROM employee WHERE employee_id = 456) as is_employee \gset \if :is_customer
SELECT * FROM customer WHERE customer_id = 123; \elif :is_employee
\echo 'is not a customer but is an employee'
SELECT * FROM employee WHERE employee_id = 456; \else
\if yes
\echo 'not a customer or employee'
\else
\echo 'this will never print'
\endif \endif

\ir or \include_relative filename

The \ir command is similar to \i, but resolves relative
file names differently. When executing in interactive mode, the two commands
behave identically. However, when invoked from a script, \ir interprets file
names relative to the directory in which the script is located, rather than
the current working directory.

\l[+] or \list[+] [ pattern ]

List the databases in the server and show their names,
owners, character set encodings, and access privileges. If pattern is
specified, only databases whose names match the pattern are listed. If + is
appended to the command name, database sizes, default tablespaces, and
descriptions are also displayed. (Size information is only available for
databases that the current user can connect to.)

\lo_export loid filename

Reads the large object with OID loid from the
database and writes it to filename. Note that this is subtly different
from the server function lo_export, which acts with the permissions of
the user that the database server runs as and on the server’s file system.

Tip

Use \lo_list to find out the large object’s OID.

\lo_import filename [ comment ]

Stores the file into a PostgreSQL large object.
Optionally, it associates the given comment with the object. Example:

foo=> \lo_import '/home/peter/pictures/photo.xcf' 'a picture of me'
lo_import 152801

The response indicates that the large object received object ID
152801, which can be used to access the newly-created large object in the
future. For the sake of readability, it is recommended to always associate a
human-readable comment with every object. Both OIDs and comments can be
viewed with the \lo_list command.

Note that this command is subtly different from the server-side
lo_import because it acts as the local user on the local file system,
rather than the server’s user and file system.

\lo_list

Shows a list of all PostgreSQL large objects currently
stored in the database, along with any comments provided for them.

\lo_unlink loid

Deletes the large object with OID loid from the
database.

Tip

Use \lo_list to find out the large object’s OID.

\o or \out [ filename ]

\o or \out [ |command ]

Arranges to save future query results to the file
filename or pipe future results to the shell command command. If
no argument is specified, the query output is reset to the standard output.

If the argument begins with |, then the entire remainder of the
line is taken to be the command to execute, and neither variable
interpolation nor backquote expansion are performed in it. The rest of the
line is simply passed literally to the shell.

“Query results” includes all tables, command
responses, and notices obtained from the database server, as well as output
of various backslash commands that query the database (such as \d);
but not error messages.

Tip

To intersperse text output in between query results, use \qecho.

\p or \print

Print the current query buffer to the standard output. If
the current query buffer is empty, the most recently executed query is printed
instead.

\password [ username ]

Changes the password of the specified user (by default,
the current user). This command prompts for the new password, encrypts it, and
sends it to the server as an ALTER ROLE command. This makes sure that
the new password does not appear in cleartext in the command history, the
server log, or elsewhere.

\prompt [ text ] name

Prompts the user to supply text, which is assigned to the
variable name. An optional prompt string, text, can be
specified. (For multiword prompts, surround the text with single quotes.)

By default, \prompt uses the terminal for input and output.
However, if the -f command line switch was used, \prompt uses
standard input and standard output.

\pset [ option [ value ] ]

This command sets options affecting the output of query
result tables. option indicates which option is to be set. The
semantics of value vary depending on the selected option. For some
options, omitting value causes the option to be toggled or unset, as
described under the particular option. If no such behavior is mentioned, then
omitting value just results in the current setting being displayed.

\pset without any arguments displays the current status of
all printing options.

Adjustable printing options are:

border

The value must be a number. In general, the higher
the number the more borders and lines the tables will have, but details depend
on the particular format. In HTML format, this will translate directly into
the border=… attribute. In most other formats only values 0 (no border), 1
(internal dividing lines), and 2 (table frame) make sense, and values above 2
will be treated the same as border = 2. The latex and latex-longtable formats
additionally allow a value of 3 to add dividing lines between data rows.

columns

Sets the target width for the wrapped format, and also
the width limit for determining whether output is wide enough to require the
pager or switch to the vertical display in expanded auto mode. Zero (the
default) causes the target width to be controlled by the environment variable
COLUMNS, or the detected screen width if COLUMNS is not set. In
addition, if columns is zero then the wrapped format only affects screen
output. If columns is nonzero then file and pipe output is wrapped to that
width as well.

expanded (or x)

If value is specified it must be either on or off,
which will enable or disable expanded mode, or auto. If value is
omitted the command toggles between the on and off settings. When expanded
mode is enabled, query results are displayed in two columns, with the column
name on the left and the data on the right. This mode is useful if the data
wouldn’t fit on the screen in the normal “horizontal” mode. In
the auto setting, the expanded mode is used whenever the query output has more
than one column and is wider than the screen; otherwise, the regular mode is
used. The auto setting is only effective in the aligned and wrapped formats.
In other formats, it always behaves as if the expanded mode is off.

fieldsep

Specifies the field separator to be used in unaligned
output format. That way one can create, for example, tab- or comma-separated
output, which other programs might prefer. To set a tab as field separator,
type \pset fieldsep ‘\t’. The default field separator is ‘|’ (a vertical
bar).

fieldsep_zero

Sets the field separator to use in unaligned output
format to a zero byte.

footer

If value is specified it must be either on or off
which will enable or disable display of the table footer (the (n rows)
count). If value is omitted the command toggles footer display on or
off.

format

Sets the output format to one of unaligned, aligned,
wrapped, html, asciidoc, latex (uses tabular), latex-longtable, or troff-ms.
Unique abbreviations are allowed. (That would mean one letter is enough.)

unaligned format writes all columns of a row on one line,
separated by the currently active field separator. This is useful for
creating output that might be intended to be read in by other programs (for
example, tab-separated or comma-separated format).

aligned format is the standard, human-readable, nicely formatted
text output; this is the default.

wrapped format is like aligned but wraps wide data values across
lines to make the output fit in the target column width. The target width is
determined as described under the columns option. Note that psql will not
attempt to wrap column header titles; therefore, wrapped format behaves the
same as aligned if the total width needed for column headers exceeds the
target.

The html, asciidoc, latex, latex-longtable, and troff-ms formats
put out tables that are intended to be included in documents using the
respective mark-up language. They are not complete documents! This might not
be necessary in HTML, but in LaTeX you must have a complete document
wrapper. latex-longtable also requires the LaTeX longtable and booktabs
packages.

linestyle

Sets the border line drawing style to one of ascii,
old-ascii, or unicode. Unique abbreviations are allowed. (That would mean one
letter is enough.) The default setting is ascii. This option only affects the
aligned and wrapped output formats.

ascii style uses plain ASCII characters. Newlines in data are
shown using a + symbol in the right-hand margin. When the wrapped format
wraps data from one line to the next without a newline character, a dot (.)
is shown in the right-hand margin of the first line, and again in the
left-hand margin of the following line.

old-ascii style uses plain ASCII characters, using the formatting
style used in PostgreSQL 8.4 and earlier. Newlines in data are shown using a
: symbol in place of the left-hand column separator. When the data is
wrapped from one line to the next without a newline character, a ; symbol is
used in place of the left-hand column separator.

unicode style uses Unicode box-drawing characters. Newlines in
data are shown using a carriage return symbol in the right-hand margin. When
the data is wrapped from one line to the next without a newline character,
an ellipsis symbol is shown in the right-hand margin of the first line, and
again in the left-hand margin of the following line.

When the border setting is greater than zero, the linestyle option
also determines the characters with which the border lines are drawn. Plain
ASCII characters work everywhere, but Unicode characters look nicer on
displays that recognize them.

null

Sets the string to be printed in place of a null value.
The default is to print nothing, which can easily be mistaken for an empty
string. For example, one might prefer \pset null ‘(null)’.

numericlocale

If value is specified it must be either on or off
which will enable or disable display of a locale-specific character to
separate groups of digits to the left of the decimal marker. If value
is omitted the command toggles between regular and locale-specific numeric
output.

pager

Controls use of a pager program for query and psql help
output. If the environment variable PAGER is set, the output is piped
to the specified program. Otherwise a platform-dependent default (such as
more) is used.

When the pager option is off, the pager program is not used. When
the pager option is on, the pager is used when appropriate, i.e., when the
output is to a terminal and will not fit on the screen. The pager option can
also be set to always, which causes the pager to be used for all terminal
output regardless of whether it fits on the screen. \pset pager without a
value toggles pager use on and off.

pager_min_lines

If pager_min_lines is set to a number greater than the
page height, the pager program will not be called unless there are at least
this many lines of output to show. The default setting is 0.

recordsep

Specifies the record (line) separator to use in unaligned
output format. The default is a newline character.

recordsep_zero

Sets the record separator to use in unaligned output
format to a zero byte.

tableattr (or T)

In HTML format, this specifies attributes to be placed
inside the table tag. This could for example be cellpadding or bgcolor. Note
that you probably don’t want to specify border here, as that is already taken
care of by \pset border. If no value is given, the table attributes are
unset.

In latex-longtable format, this controls the proportional width of
each column containing a left-aligned data type. It is specified as a
whitespace-separated list of values, e.g. ‘0.2 0.2 0.6’. Unspecified output
columns use the last specified value.

title (or C)

Sets the table title for any subsequently printed tables.
This can be used to give your output descriptive tags. If no value is
given, the title is unset.

tuples_only (or t)

If value is specified it must be either on or off
which will enable or disable tuples-only mode. If value is omitted the
command toggles between regular and tuples-only output. Regular output
includes extra information such as column headers, titles, and various
footers. In tuples-only mode, only actual table data is shown.

unicode_border_linestyle

Sets the border drawing style for the unicode line style
to one of single or double.

unicode_column_linestyle

Sets the column drawing style for the unicode line style
to one of single or double.

unicode_header_linestyle

Sets the header drawing style for the unicode line style
to one of single or double.

Illustrations of how these different formats look can be seen in
the EXAMPLES section.

Tip

There are various shortcut commands for \pset. See \a, \C,
\f, \H, \t, \T, and \x.

\q or \quit

Quits the psql program. In a script file, only execution
of that script is terminated.

\qecho text [ … ]

This command is identical to \echo except that the
output will be written to the query output channel, as set by \o.

\r or \reset

Resets (clears) the query buffer.

\s [ filename ]

Print psql’s command line history to filename. If
filename is omitted, the history is written to the standard output
(using the pager if appropriate). This command is not available if psql was
built without Readline support.

\set [ name [ value [ … ] ] ]

Sets the psql variable name to value, or if
more than one value is given, to the concatenation of all of them. If only one
argument is given, the variable is set to an empty-string value. To unset a
variable, use the \unset command.

\set without any arguments displays the names and values of
all currently-set psql variables.

Valid variable names can contain letters, digits, and underscores.
See the section Variables below for details. Variable names are
case-sensitive.

Certain variables are special, in that they control psql’s
behavior or are automatically set to reflect connection state. These
variables are documented in Variables, below.

Note

This command is unrelated to the SQL command SET(7).

\setenv name [ value ]

Sets the environment variable name to
value, or if the value is not supplied, unsets the environment
variable. Example:

testdb=> \setenv PAGER less
testdb=> \setenv LESS -imx4F

\sf[+] function_description

This command fetches and shows the definition of the
named function, in the form of a CREATE OR REPLACE FUNCTION command.
The definition is printed to the current query output channel, as set by
\o.

The target function can be specified by name alone, or by name and
arguments, for example foo(integer, text). The argument types must be given
if there is more than one function of the same name.

If + is appended to the command name, then the output lines are
numbered, with the first line of the function body being line 1.

Unlike most other meta-commands, the entire remainder of the line
is always taken to be the argument(s) of \sf, and neither variable
interpolation nor backquote expansion are performed in the arguments.

\sv[+] view_name

This command fetches and shows the definition of the
named view, in the form of a CREATE OR REPLACE VIEW command. The
definition is printed to the current query output channel, as set by
\o.

If + is appended to the command name, then the output lines are
numbered from 1.

Unlike most other meta-commands, the entire remainder of the line
is always taken to be the argument(s) of \sv, and neither variable
interpolation nor backquote expansion are performed in the arguments.

\t

Toggles the display of output column name headings and
row count footer. This command is equivalent to \pset tuples_only and is
provided for convenience.

\T table_options

Specifies attributes to be placed within the table tag in
HTML output format. This command is equivalent to \pset tableattr
table_options.

\timing [ on | off ]

With a parameter, turns displaying of how long each SQL
statement takes on or off. Without a parameter, toggles the display between on
and off. The display is in milliseconds; intervals longer than 1 second are
also shown in minutes:seconds format, with hours and days fields added if
needed.

\unset name

Unsets (deletes) the psql variable name.

Most variables that control psql’s behavior cannot be unset;
instead, an \unset command is interpreted as setting them to their default
values. See Variables, below.

\w or \write filename

\w or \write |command

Writes the current query buffer to the file
filename or pipes it to the shell command command. If the
current query buffer is empty, the most recently executed query is written
instead.

If the argument begins with |, then the entire remainder of the
line is taken to be the command to execute, and neither variable
interpolation nor backquote expansion are performed in it. The rest of the
line is simply passed literally to the shell.

\watch [ seconds ]

Repeatedly execute the current query buffer (as \g does)
until interrupted or the query fails. Wait the specified number of seconds
(default 2) between executions. Each query result is displayed with a header
that includes the \pset title string (if any), the time as of query start, and
the delay interval.

If the current query buffer is empty, the most recently sent query
is re-executed instead.

\x [ on | off | auto ]

Sets or toggles expanded table formatting mode. As such
it is equivalent to \pset expanded.

\z [ pattern ]

Lists tables, views and sequences with their associated
access privileges. If a pattern is specified, only tables, views and
sequences whose names match the pattern are listed.

This is an alias for \dp (“display
privileges”).

\! [ command ]

With no argument, escapes to a sub-shell; psql resumes
when the sub-shell exits. With an argument, executes the shell command
command.

Unlike most other meta-commands, the entire remainder of the line
is always taken to be the argument(s) of \!, and neither variable
interpolation nor backquote expansion are performed in the arguments. The
rest of the line is simply passed literally to the shell.

\? [ topic ]

Shows help information. The optional topic
parameter (defaulting to commands) selects which part of psql is explained:
commands describes psql’s backslash commands; options describes the
command-line options that can be passed to psql; and variables shows help
about psql configuration variables.

Patterns

The various \d commands accept a pattern parameter to
specify the object name(s) to be displayed. In the simplest case, a pattern
is just the exact name of the object. The characters within a pattern are
normally folded to lower case, just as in SQL names; for example, \dt FOO
will display the table named foo. As in SQL names, placing double quotes
around a pattern stops folding to lower case. Should you need to include an
actual double quote character in a pattern, write it as a pair of double
quotes within a double-quote sequence; again this is in accord with the
rules for SQL quoted identifiers. For example, \dt
«FOO»»BAR» will display the table named FOO»BAR
(not foo»bar). Unlike the normal rules for SQL names, you can put
double quotes around just part of a pattern, for instance \dt
FOO»FOO»BAR will display the table named fooFOObar.

Whenever the pattern parameter is omitted completely, the
\d commands display all objects that are visible in the current schema
search path — this is equivalent to using * as the pattern. (An
object is said to be visible if its containing schema is in the search path
and no object of the same kind and name appears earlier in the search path.
This is equivalent to the statement that the object can be referenced by
name without explicit schema qualification.) To see all objects in the
database regardless of visibility, use *.* as the pattern.

Within a pattern, * matches any sequence of characters (including
no characters) and ? matches any single character. (This notation is
comparable to Unix shell file name patterns.) For example, \dt int* displays
tables whose names begin with int. But within double quotes, * and ? lose
these special meanings and are just matched literally.

A pattern that contains a dot (.) is interpreted as a schema name
pattern followed by an object name pattern. For example, \dt foo*.*bar*
displays all tables whose table name includes bar that are in schemas whose
schema name starts with foo. When no dot appears, then the pattern matches
only objects that are visible in the current schema search path. Again, a
dot within double quotes loses its special meaning and is matched
literally.

Advanced users can use regular-expression notations such as
character classes, for example [0-9] to match any digit. All regular
expression special characters work as specified in Section 9.7.3,
except for . which is taken as a separator as mentioned above, * which is
translated to the regular-expression notation .*, ? which is translated to
., and $ which is matched literally. You can emulate these pattern
characters at need by writing ? for ., (R+|) for R*, or
(R|) for R?. $ is not needed as a regular-expression character
since the pattern must match the whole name, unlike the usual interpretation
of regular expressions (in other words, $ is automatically appended to your
pattern). Write * at the beginning and/or end if you don’t wish the pattern
to be anchored. Note that within double quotes, all regular expression
special characters lose their special meanings and are matched literally.
Also, the regular expression special characters are matched literally in
operator name patterns (i.e., the argument of \do).

Advanced Features¶

Variables

psql provides variable substitution features similar to common
Unix command shells. Variables are simply name/value pairs, where the value
can be any string of any length. The name must consist of letters (including
non-Latin letters), digits, and underscores.

To set a variable, use the psql meta-command \set. For
example,

sets the variable foo to the value bar. To retrieve the content of
the variable, precede the name with a colon, for example:

This works in both regular SQL commands and meta-commands; there
is more detail in SQL Interpolation, below.

If you call \set without a second argument, the variable is
set to an empty-string value. To unset (i.e., delete) a variable, use the
command \unset. To show the values of all variables, call \set
without any argument.

Note

The arguments of \set are subject to the same substitution
rules as with other commands. Thus you can construct interesting references
such as \set :foo ‘something’ and get “soft links” or
“variable variables” of Perl or PHP fame, respectively.
Unfortunately (or fortunately?), there is no way to do anything useful with
these constructs. On the other hand, \set bar :foo is a perfectly valid way
to copy a variable.

A number of these variables are treated specially by psql. They
represent certain option settings that can be changed at run time by
altering the value of the variable, or in some cases represent changeable
state of psql. By convention, all specially treated variables’ names consist
of all upper-case ASCII letters (and possibly digits and underscores). To
ensure maximum compatibility in the future, avoid using such variable names
for your own purposes.

Variables that control psql’s behavior generally cannot be unset
or set to invalid values. An \unset command is allowed but is interpreted as
setting the variable to its default value. A \set command without a second
argument is interpreted as setting the variable to on, for control variables
that accept that value, and is rejected for others. Also, control variables
that accept the values on and off will also accept other common spellings of
Boolean values, such as true and false.

The specially treated variables are:

AUTOCOMMIT

When on (the default), each SQL command is automatically
committed upon successful completion. To postpone commit in this mode, you
must enter a BEGIN or START TRANSACTION SQL command. When off or
unset, SQL commands are not committed until you explicitly issue COMMIT
or END. The autocommit-off mode works by issuing an implicit
BEGIN for you, just before any command that is not already in a
transaction block and is not itself a BEGIN or other
transaction-control command, nor a command that cannot be executed inside a
transaction block (such as VACUUM).

Note

In autocommit-off mode, you must explicitly abandon any failed transaction by
entering ABORT or ROLLBACK. Also keep in mind that if you exit
the session without committing, your work will be lost.

Note

The autocommit-on mode is PostgreSQL’s traditional behavior, but autocommit-off
is closer to the SQL spec. If you prefer autocommit-off, you might wish to set
it in the system-wide psqlrc file or your ~/.psqlrc file.

COMP_KEYWORD_CASE

Determines which letter case to use when completing an
SQL key word. If set to lower or upper, the completed word will be in lower or
upper case, respectively. If set to preserve-lower or preserve-upper (the
default), the completed word will be in the case of the word already entered,
but words being completed without anything entered will be in lower or upper
case, respectively.

DBNAME

The name of the database you are currently connected to.
This is set every time you connect to a database (including program start-up),
but can be changed or unset.

ECHO

If set to all, all nonempty input lines are printed to
standard output as they are read. (This does not apply to lines read
interactively.) To select this behavior on program start-up, use the switch
-a. If set to queries, psql prints each query to standard output as it
is sent to the server. The switch to select this behavior is -e. If set
to errors, then only failed queries are displayed on standard error output.
The switch for this behavior is -b. If set to none (the default), then
no queries are displayed.

ECHO_HIDDEN

When this variable is set to on and a backslash command
queries the database, the query is first shown. This feature helps you to
study PostgreSQL internals and provide similar functionality in your own
programs. (To select this behavior on program start-up, use the switch
-E.) If you set this variable to the value noexec, the queries are just
shown but are not actually sent to the server and executed. The default value
is off.

ENCODING

The current client character set encoding. This is set
every time you connect to a database (including program start-up), and when
you change the encoding with \encoding, but it can be changed or unset.

FETCH_COUNT

If this variable is set to an integer value greater than
zero, the results of SELECT queries are fetched and displayed in groups
of that many rows, rather than the default behavior of collecting the entire
result set before display. Therefore only a limited amount of memory is used,
regardless of the size of the result set. Settings of 100 to 1000 are commonly
used when enabling this feature. Keep in mind that when using this feature, a
query might fail after having already displayed some rows.

Tip

Although you can use any output format with this feature, the default aligned
format tends to look bad because each group of FETCH_COUNT rows will be
formatted separately, leading to varying column widths across the row groups.
The other output formats work better.

HISTCONTROL

If this variable is set to ignorespace, lines which begin
with a space are not entered into the history list. If set to a value of
ignoredups, lines matching the previous history line are not entered. A value
of ignoreboth combines the two options. If set to none (the default), all
lines read in interactive mode are saved on the history list.

Note

This feature was shamelessly plagiarized from Bash.

HISTFILE

The file name that will be used to store the history
list. If unset, the file name is taken from the PSQL_HISTORY
environment variable. If that is not set either, the default is
~/.psql_history, or %APPDATA%\postgresql\psql_history on Windows. For example,
putting:

\set HISTFILE ~/.psql_history- :DBNAME

in ~/.psqlrc will cause psql to maintain a separate history for
each database.

Note

This feature was shamelessly plagiarized from Bash.

HISTSIZE

The maximum number of commands to store in the command
history (default 500). If set to a negative value, no limit is applied.

Note

This feature was shamelessly plagiarized from Bash.

HOST

The database server host you are currently connected to.
This is set every time you connect to a database (including program start-up),
but can be changed or unset.

IGNOREEOF

If set to 1 or less, sending an EOF character (usually
Control+D) to an interactive session of psql will terminate the application.
If set to a larger numeric value, that many consecutive EOF characters must be
typed to make an interactive session terminate. If the variable is set to a
non-numeric value, it is interpreted as 10. The default is 0.

Note

This feature was shamelessly plagiarized from Bash.

LASTOID

The value of the last affected OID, as returned from an
INSERT or \lo_import command. This variable is only guaranteed
to be valid until after the result of the next SQL command has been
displayed.

ON_ERROR_ROLLBACK

When set to on, if a statement in a transaction block
generates an error, the error is ignored and the transaction continues. When
set to interactive, such errors are only ignored in interactive sessions, and
not when reading script files. When set to off (the default), a statement in a
transaction block that generates an error aborts the entire transaction. The
error rollback mode works by issuing an implicit SAVEPOINT for you,
just before each command that is in a transaction block, and then rolling back
to the savepoint if the command fails.

ON_ERROR_STOP

By default, command processing continues after an error.
When this variable is set to on, processing will instead stop immediately. In
interactive mode, psql will return to the command prompt; otherwise, psql will
exit, returning error code 3 to distinguish this case from fatal error
conditions, which are reported using error code 1. In either case, any
currently running scripts (the top-level script, if any, and any other scripts
which it may have in invoked) will be terminated immediately. If the top-level
command string contained multiple SQL commands, processing will stop with the
current command.

PORT

The database server port to which you are currently
connected. This is set every time you connect to a database (including program
start-up), but can be changed or unset.

PROMPT1

PROMPT2

PROMPT3

These specify what the prompts psql issues should look
like. See Prompting below.

QUIET

Setting this variable to on is equivalent to the command
line option -q. It is probably not too useful in interactive
mode.

SERVER_VERSION_NAME

SERVER_VERSION_NUM

The server’s version number as a string, for example
9.6.2, 10.1 or 11beta1, and in numeric form, for example 90602 or 100001.
These are set every time you connect to a database (including program
start-up), but can be changed or unset.

SHOW_CONTEXT

This variable can be set to the values never, errors, or
always to control whether CONTEXT fields are displayed in messages from the
server. The default is errors (meaning that context will be shown in error
messages, but not in notice or warning messages). This setting has no effect
when VERBOSITY is set to terse. (See also \errverbose, for use
when you want a verbose version of the error you just got.)

SINGLELINE

Setting this variable to on is equivalent to the command
line option -S.

SINGLESTEP

Setting this variable to on is equivalent to the command
line option -s.

USER

The database user you are currently connected as. This is
set every time you connect to a database (including program start-up), but can
be changed or unset.

VERBOSITY

This variable can be set to the values default, verbose,
or terse to control the verbosity of error reports. (See also
\errverbose, for use when you want a verbose version of the error you
just got.)

VERSION

VERSION_NAME

VERSION_NUM

These variables are set at program start-up to reflect
psql’s version, respectively as a verbose string, a short string (e.g., 9.6.2,
10.1, or 11beta1), and a number (e.g., 90602 or 100001). They can be changed
or unset.

SQL Interpolation

A key feature of psql variables is that you can substitute
(“interpolate”) them into regular SQL statements, as well as
the arguments of meta-commands. Furthermore, psql provides facilities for
ensuring that variable values used as SQL literals and identifiers are
properly quoted. The syntax for interpolating a value without any quoting is
to prepend the variable name with a colon (:). For example,

testdb=> \set foo 'my_table'
testdb=> SELECT * FROM :foo;

would query the table my_table. Note that this may be unsafe: the
value of the variable is copied literally, so it can contain unbalanced
quotes, or even backslash commands. You must make sure that it makes sense
where you put it.

When a value is to be used as an SQL literal or identifier, it is
safest to arrange for it to be quoted. To quote the value of a variable as
an SQL literal, write a colon followed by the variable name in single
quotes. To quote the value as an SQL identifier, write a colon followed by
the variable name in double quotes. These constructs deal correctly with
quotes and other special characters embedded within the variable value. The
previous example would be more safely written this way:

testdb=> \set foo 'my_table'
testdb=> SELECT * FROM :"foo";

Variable interpolation will not be performed within quoted SQL
literals and identifiers. Therefore, a construction such as ‘:foo’ doesn’t
work to produce a quoted literal from a variable’s value (and it would be
unsafe if it did work, since it wouldn’t correctly handle quotes embedded in
the value).

One example use of this mechanism is to copy the contents of a
file into a table column. First load the file into a variable and then
interpolate the variable’s value as a quoted string:

testdb=> \set content `cat my_file.txt`
testdb=> INSERT INTO my_table VALUES (:'content');

(Note that this still won’t work if my_file.txt contains NUL
bytes. psql does not support embedded NUL bytes in variable values.)

Since colons can legally appear in SQL commands, an apparent
attempt at interpolation (that is, :name, :’name’, or :»name») is
not replaced unless the named variable is currently set. In any case, you
can escape a colon with a backslash to protect it from substitution.

The colon syntax for variables is standard SQL for embedded query
languages, such as ECPG. The colon syntaxes for array slices and type casts
are PostgreSQL extensions, which can sometimes conflict with the standard
usage. The colon-quote syntax for escaping a variable’s value as an SQL
literal or identifier is a psql extension.

Prompting

The prompts psql issues can be customized to your preference. The
three variables PROMPT1, PROMPT2, and PROMPT3 contain
strings and special escape sequences that describe the appearance of the
prompt. Prompt 1 is the normal prompt that is issued when psql requests a
new command. Prompt 2 is issued when more input is expected during command
entry, for example because the command was not terminated with a semicolon
or a quote was not closed. Prompt 3 is issued when you are running an SQL
COPY FROM STDIN command and you need to type in a row value on the
terminal.

The value of the selected prompt variable is printed literally,
except where a percent sign (%) is encountered. Depending on the next
character, certain other text is substituted instead. Defined substitutions
are:

%M

The full host name (with domain name) of the database
server, or [local] if the connection is over a Unix domain socket, or
[local:/dir/name], if the Unix domain socket is not at the compiled in
default location.

%m

The host name of the database server, truncated at the
first dot, or [local] if the connection is over a Unix domain socket.

%>

The port number at which the database server is
listening.

%n

The database session user name. (The expansion of this
value might change during a database session as the result of the command
SET SESSION AUTHORIZATION.)

%/

The name of the current database.

%~

Like %/, but the output is ~ (tilde) if the database is
your default database.

%#

If the session user is a database superuser, then a #,
otherwise a >. (The expansion of this value might change during a database
session as the result of the command SET SESSION AUTHORIZATION.)

%p

The process ID of the backend currently connected
to.

%R

In prompt 1 normally =, but @ if the session is in an
inactive branch of a conditional block, or ^ if in single-line mode, or ! if
the session is disconnected from the database (which can happen if
\connect fails). In prompt 2 %R is replaced by a character that depends
on why psql expects more input: — if the command simply wasn’t terminated yet,
but * if there is an unfinished /* … */ comment, a single quote if there is
an unfinished quoted string, a double quote if there is an unfinished quoted
identifier, a dollar sign if there is an unfinished dollar-quoted string, or (
if there is an unmatched left parenthesis. In prompt 3 %R doesn’t produce
anything.

%x

Transaction status: an empty string when not in a
transaction block, or * when in a transaction block, or ! when in a failed
transaction block, or ? when the transaction state is indeterminate (for
example, because there is no connection).

%l

The line number inside the current statement, starting
from 1.

%digits

The character with the indicated octal code is
substituted.

%:name:

The value of the psql variable name. See the
section Variables for details.

%`command`

The output of command, similar to ordinary
“back-tick” substitution.

%[ … %]

Prompts can contain terminal control characters which,
for example, change the color, background, or style of the prompt text, or
change the title of the terminal window. In order for the line editing
features of Readline to work properly, these non-printing control characters
must be designated as invisible by surrounding them with %[ and %]. Multiple
pairs of these can occur within the prompt. For example:

testdb=> \set PROMPT1 '%[%033[1;33;40m%]%n@%/%R%[%033[0m%]%# '

results in a boldfaced (1;) yellow-on-black (33;40) prompt on
VT100-compatible, color-capable terminals.

To insert a percent sign into your prompt, write %%. The default prompts are
‘%/%R%# ‘ for prompts 1 and 2, and ‘>> ‘ for prompt 3.

Note

This feature was shamelessly plagiarized from tcsh.

Command-Line Editing

psql supports the Readline library for convenient line editing and
retrieval. The command history is automatically saved when psql exits and is
reloaded when psql starts up. Tab-completion is also supported, although the
completion logic makes no claim to be an SQL parser. The queries generated
by tab-completion can also interfere with other SQL commands, e.g. SET
TRANSACTION ISOLATION LEVEL. If for some reason you do not like the tab
completion, you can turn it off by putting this in a file named .inputrc in
your home directory:

$if psql
set disable-completion on
$endif

(This is not a psql but a Readline feature. Read its documentation
for further details.)

ENVIRONMENT¶

COLUMNS

If \pset columns is zero, controls the width for the
wrapped format and width for determining if wide output requires the pager or
should be switched to the vertical format in expanded auto mode.

PAGER

If the query results do not fit on the screen, they are
piped through this command. Typical values are more or less. The default is
platform-dependent. Use of the pager can be disabled by setting PAGER
to empty, or by using pager-related options of the \pset command.

PGDATABASE

PGHOST

PGPORT

PGUSER

Default connection parameters (see
Section 33.14).

PSQL_EDITOR

EDITOR

VISUAL

Editor used by the \e, \ef, and \ev
commands. These variables are examined in the order listed; the first that is
set is used.

The built-in default editors are vi on Unix systems and
notepad.exe on Windows systems.

PSQL_EDITOR_LINENUMBER_ARG

When \e, \ef, or \ev is used with a
line number argument, this variable specifies the command-line argument used
to pass the starting line number to the user’s editor. For editors such as
Emacs or vi, this is a plus sign. Include a trailing space in the value of the
variable if there needs to be space between the option name and the line
number. Examples:

PSQL_EDITOR_LINENUMBER_ARG='+'
PSQL_EDITOR_LINENUMBER_ARG='--line '

The default is + on Unix systems (corresponding to the default
editor vi, and useful for many other common editors); but there is no
default on Windows systems.

PSQL_HISTORY

Alternative location for the command history file. Tilde
(~) expansion is performed.

PSQLRC

Alternative location of the user’s .psqlrc file. Tilde
(~) expansion is performed.

SHELL

Command executed by the \! command.

TMPDIR

Directory for storing temporary files. The default is
/tmp.

This utility, like most other PostgreSQL utilities, also uses the
environment variables supported by libpq (see Section 33.14).

FILES¶

psqlrc and ~/.psqlrc

Unless it is passed an -X option, psql attempts to
read and execute commands from the system-wide startup file (psqlrc) and then
the user’s personal startup file (~/.psqlrc), after connecting to the database
but before accepting normal commands. These files can be used to set up the
client and/or the server to taste, typically with \set and SET
commands.

The system-wide startup file is named psqlrc and is sought in the
installation’s “system configuration” directory, which is most
reliably identified by running pg_config —sysconfdir. By default this
directory will be ../etc/ relative to the directory containing the
PostgreSQL executables. The name of this directory can be set explicitly via
the PGSYSCONFDIR environment variable.

The user’s personal startup file is named .psqlrc and is sought in
the invoking user’s home directory. On Windows, which lacks such a concept,
the personal startup file is named %APPDATA%\postgresql\psqlrc.conf. The
location of the user’s startup file can be set explicitly via the
PSQLRC environment variable.

Both the system-wide startup file and the user’s personal startup
file can be made psql-version-specific by appending a dash and the
PostgreSQL major or minor release number to the file name, for example
~/.psqlrc-9.2 or ~/.psqlrc-9.2.5. The most specific version-matching file
will be read in preference to a non-version-specific file.

.psql_history

The command-line history is stored in the file
~/.psql_history, or %APPDATA%\postgresql\psql_history on Windows.

The location of the history file can be set explicitly via the
HISTFILE psql variable or the PSQL_HISTORY environment
variable.

NOTES¶

•psql works best with servers of the same or an
older major version. Backslash commands are particularly likely to fail if the
server is of a newer version than psql itself. However, backslash commands of
the \d family should work with servers of versions back to 7.4, though not
necessarily with servers newer than psql itself. The general functionality of
running SQL commands and displaying query results should also work with
servers of a newer major version, but this cannot be guaranteed in all cases.

If you want to use psql to connect to several servers of different
major versions, it is recommended that you use the newest version of psql.
Alternatively, you can keep around a copy of psql from each major version
and be sure to use the version that matches the respective server. But in
practice, this additional complication should not be necessary.

•Before PostgreSQL 9.6, the -c option
implied -X (—no-psqlrc); this is no longer the case.

•Before PostgreSQL 8.4, psql allowed the first
argument of a single-letter backslash command to start directly after the
command, without intervening whitespace. Now, some whitespace is
required.

NOTES FOR WINDOWS USERS¶

psql is built as a “console application”. Since the
Windows console windows use a different encoding than the rest of the
system, you must take special care when using 8-bit characters within psql.
If psql detects a problematic console code page, it will warn you at
startup. To change the console code page, two things are necessary:

•Set the code page by entering cmd.exe /c chcp
1252
. (1252 is a code page that is appropriate for German; replace it with
your value.) If you are using Cygwin, you can put this command in
/etc/profile.

•Set the console font to Lucida Console, because
the raster font does not work with the ANSI code page.

EXAMPLES¶

The first example shows how to spread a command over several lines
of input. Notice the changing prompt:

testdb=> CREATE TABLE my_table (
testdb(>  first integer not null default 0,
testdb(>  second text)
testdb-> ;
CREATE TABLE

Now look at the table definition again:

testdb=> \d my_table

Table "public.my_table"
Column | Type | Collation | Nullable | Default --------+---------+-----------+----------+---------
first | integer | | not null | 0
second | text | | |

Now we change the prompt to something more interesting:

testdb=> \set PROMPT1 '%n@%m %~%R%# '
peter@localhost testdb=>

Let’s assume you have filled the table with data and want to take
a look at it:

peter@localhost testdb=> SELECT * FROM my_table;

first | second -------+--------
1 | one
2 | two
3 | three
4 | four (4 rows)

You can display tables in different ways by using the \pset
command:

peter@localhost testdb=> \pset border 2
Border style is 2.
peter@localhost testdb=> SELECT * FROM my_table;
+-------+--------+
| first | second |
+-------+--------+
|     1 | one    |
|     2 | two    |
|     3 | three  |
|     4 | four   |
+-------+--------+
(4 rows)
peter@localhost testdb=> \pset border 0
Border style is 0.
peter@localhost testdb=> SELECT * FROM my_table;
first second
----- ------

1 one
2 two
3 three
4 four (4 rows) peter@localhost testdb=> \pset border 1 Border style is 1. peter@localhost testdb=> \pset format unaligned Output format is unaligned. peter@localhost testdb=> \pset fieldsep "," Field separator is ",". peter@localhost testdb=> \pset tuples_only Showing only tuples. peter@localhost testdb=> SELECT second, first FROM my_table; one,1 two,2 three,3 four,4

Alternatively, use the short commands:

peter@localhost testdb=> \a \t \x
Output format is aligned.
Tuples only is off.
Expanded display is on.
peter@localhost testdb=> SELECT * FROM my_table;
-[ RECORD 1 ]-
first  | 1
second | one
-[ RECORD 2 ]-
first  | 2
second | two
-[ RECORD 3 ]-
first  | 3
second | three
-[ RECORD 4 ]-
first  | 4
second | four

When suitable, query results can be shown in a crosstab
representation with the \crosstabview command:

testdb=> SELECT first, second, first > 2 AS gt2 FROM my_table;

first | second | gt2 -------+--------+-----
1 | one | f
2 | two | f
3 | three | t
4 | four | t (4 rows) testdb=> \crosstabview first second
first | one | two | three | four -------+-----+-----+-------+------
1 | f | | |
2 | | f | |
3 | | | t |
4 | | | | t (4 rows)

This second example shows a multiplication table with rows sorted
in reverse numerical order and columns with an independent, ascending
numerical order.

testdb=> SELECT t1.first as "A", t2.first+100 AS "B", t1.first*(t2.first+100) as "AxB",
testdb(> row_number() over(order by t2.first) AS ord
testdb(> FROM my_table t1 CROSS JOIN my_table t2 ORDER BY 1 DESC
testdb(> \crosstabview "A" "B" "AxB" ord

A | 101 | 102 | 103 | 104 ---+-----+-----+-----+-----
4 | 404 | 408 | 412 | 416
3 | 303 | 306 | 309 | 312
2 | 202 | 204 | 206 | 208
1 | 101 | 102 | 103 | 104 (4 rows)

I have installed PostgreSQL, wanting to set up a new database, everything is going fine, until I am trying to use the € sign. And then I knew, that warning I get in the beginning is for a reason.

The warning I am getting at starting up my psql shell is:

WARNING: Console code page (850) differs from Windows code page (1252)
         8-bit characters might not work correctly. See psql reference
         page "Notes for Windows users" for details.

So I am going to do as I am told (from PostgreSQL Documentation 9.2 — psql):


Notes for Windows Users

psql is built as a «console application». Since the Windows console windows use a different encoding than the rest of the system, you must take special care when using 8-bit characters within psql. If psql detects a problematic console code page, it will warn you at startup. To change the console code page, two things are necessary:

  • Set the code page by entering cmd.exe /c chcp 1252. (1252 is a code page that is appropriate for German; replace it with your value.) If you are using Cygwin, you can put this command in /etc/profile.
  • Set the console font to Lucida Console, because the raster font does not work with the ANSI code page.

When I type the cmd.exe /c chcp 1252 command I get a syntax error. So psql, doesn’t recognize the command.
Out of desperation, I was trying to do something in cmd.exe itself, does not work either.

I work in Windows 7 — 64Bit.

psql

psqlPostgreSQL interactive terminal

Synopsis

psql [option…] [dbname [username]]

Description

psql is a terminal-based front-end to PostgreSQL. It enables you to type in queries interactively, issue them to PostgreSQL, and see the query results. Alternatively, input can be from a file or from command line arguments. In addition, psql provides a number of meta-commands and various shell-like features to facilitate writing scripts and automating a wide variety of tasks.

Options

-a

--echo-all

Print all nonempty input lines to standard output as they are read. (This does not apply to lines read interactively.) This is equivalent to setting the variable ECHO to all.

-A

--no-align

Switches to unaligned output mode. (The default output mode is otherwise aligned.) This is equivalent to \pset format unaligned.

-b

--echo-errors

Print failed SQL commands to standard error output. This is equivalent to setting the variable ECHO to errors.

-c command

--command=command

Specifies that psql is to execute the given command string, command. This option can be repeated and combined in any order with the -f option. When either -c or -f is specified, psql does not read commands from standard input; instead it terminates after processing all the -c and -f options in sequence.

command must be either a command string that is completely parsable by the server (i.e., it contains no psql-specific features), or a single backslash command. Thus you cannot mix SQL and psql meta-commands within a -c option. To achieve that, you could use repeated -c options or pipe the string into psql, for example:

psql -c '\x' -c 'SELECT * FROM foo;'

or

echo '\x \\ SELECT * FROM foo;' | psql

(\\ is the separator meta-command.)

Each SQL command string passed to -c is sent to the server as a single request. Because of this, the server executes it as a single transaction even if the string contains multiple SQL commands, unless there are explicit BEGIN/COMMIT commands included in the string to divide it into multiple transactions. (See Section 53.2.2.1 for more details about how the server handles multi-query strings.) Also, psql only prints the result of the last SQL command in the string. This is different from the behavior when the same string is read from a file or fed to psql‘s standard input, because then psql sends each SQL command separately.

Because of this behavior, putting more than one SQL command in a single -c string often has unexpected results. It’s better to use repeated -c commands or feed multiple commands to psql‘s standard input, either using echo as illustrated above, or via a shell here-document, for example:

psql <<EOF
\x
SELECT * FROM foo;
EOF
-d dbname

--dbname=dbname

Specifies the name of the database to connect to. This is equivalent to specifying dbname as the first non-option argument on the command line.

If this parameter contains an = sign or starts with a valid URI prefix (postgresql:// or postgres://), it is treated as a conninfo string. See Section 34.1.1 for more information.

-e

--echo-queries

Copy all SQL commands sent to the server to standard output as well. This is equivalent to setting the variable ECHO to queries.

-E

--echo-hidden

Echo the actual queries generated by \d and other backslash commands. You can use this to study psql‘s internal operations. This is equivalent to setting the variable ECHO_HIDDEN to on.

-f filename

--file=filename

Read commands from the file filename, rather than standard input. This option can be repeated and combined in any order with the -c option. When either -c or -f is specified, psql does not read commands from standard input; instead it terminates after processing all the -c and -f options in sequence. Except for that, this option is largely equivalent to the meta-command \i.

If filename is - (hyphen), then standard input is read until an EOF indication or \q meta-command. This can be used to intersperse interactive input with input from files. Note however that Readline is not used in this case (much as if -n had been specified).

Using this option is subtly different from writing psql < filename. In general, both will do what you expect, but using -f enables some nice features such as error messages with line numbers. There is also a slight chance that using this option will reduce the start-up overhead. On the other hand, the variant using the shell’s input redirection is (in theory) guaranteed to yield exactly the same output you would have received had you entered everything by hand.

-F separator

--field-separator=separator

Use separator as the field separator for unaligned output. This is equivalent to \pset fieldsep or \f.

-h hostname

--host=hostname

Specifies the host name of the machine on which the server is running. If the value begins with a slash, it is used as the directory for the Unix-domain socket.

-H

--html

Turn on HTML tabular output. This is equivalent to \pset format html or the \H command.

-l

--list

List all available databases, then exit. Other non-connection options are ignored. This is similar to the meta-command \list.

When this option is used, psql will connect to the database postgres, unless a different database is named on the command line (option -d or non-option argument, possibly via a service entry, but not via an environment variable).

-L filename

--log-file=filename

Write all query output into file filename, in addition to the normal output destination.

-n

--no-readline

Do not use Readline for line editing and do not use the command history. This can be useful to turn off tab expansion when cutting and pasting.

-o filename

--output=filename

Put all query output into file filename. This is equivalent to the command \o.

-p port

--port=port

Specifies the TCP port or the local Unix-domain socket file extension on which the server is listening for connections. Defaults to the value of the PGPORT environment variable or, if not set, to the port specified at compile time, usually 5432.

-P assignment

--pset=assignment

Specifies printing options, in the style of \pset. Note that here you have to separate name and value with an equal sign instead of a space. For example, to set the output format to LaTeX, you could write -P format=latex.

-q

--quiet

Specifies that psql should do its work quietly. By default, it prints welcome messages and various informational output. If this option is used, none of this happens. This is useful with the -c option. This is equivalent to setting the variable QUIET to on.

-R separator

--record-separator=separator

Use separator as the record separator for unaligned output. This is equivalent to \pset recordsep.

-s

--single-step

Run in single-step mode. That means the user is prompted before each command is sent to the server, with the option to cancel execution as well. Use this to debug scripts.

-S

--single-line

Runs in single-line mode where a newline terminates an SQL command, as a semicolon does.

This mode is provided for those who insist on it, but you are not necessarily encouraged to use it. In particular, if you mix SQL and meta-commands on a line the order of execution might not always be clear to the inexperienced user.

-t

--tuples-only

Turn off printing of column names and result row count footers, etc. This is equivalent to \t or \pset tuples_only.

-T table_options

--table-attr=table_options

Specifies options to be placed within the HTML table tag. See \pset tableattr for details.

-U username

--username=username

Connect to the database as the user username instead of the default. (You must have permission to do so, of course.)

-v assignment

--set=assignment

--variable=assignment

Perform a variable assignment, like the \set meta-command. Note that you must separate name and value, if any, by an equal sign on the command line. To unset a variable, leave off the equal sign. To set a variable with an empty value, use the equal sign but leave off the value. These assignments are done during command line processing, so variables that reflect connection state will get overwritten later.

-V

--version

Print the psql version and exit.

-w

--no-password

Never issue a password prompt. If the server requires password authentication and a password is not available by other means such as a .pgpass file, the connection attempt will fail. This option can be useful in batch jobs and scripts where no user is present to enter a password.

Note that this option will remain set for the entire session, and so it affects uses of the meta-command \connect as well as the initial connection attempt.

-W

--password

Force psql to prompt for a password before connecting to a database.

This option is never essential, since psql will automatically prompt for a password if the server demands password authentication. However, psql will waste a connection attempt finding out that the server wants a password. In some cases it is worth typing -W to avoid the extra connection attempt.

Note that this option will remain set for the entire session, and so it affects uses of the meta-command \connect as well as the initial connection attempt.

-x

--expanded

Turn on the expanded table formatting mode. This is equivalent to \x or \pset expanded.

-X,

--no-psqlrc

Do not read the start-up file (neither the system-wide psqlrc file nor the user’s ~/.psqlrc file).

-z

--field-separator-zero

Set the field separator for unaligned output to a zero byte. This is equivalent to \pset fieldsep_zero.

-0

--record-separator-zero

Set the record separator for unaligned output to a zero byte. This is useful for interfacing, for example, with xargs -0. This is equivalent to \pset recordsep_zero.

-1

--single-transaction

This option can only be used in combination with one or more -c and/or -f options. It causes psql to issue a BEGIN command before the first such option and a COMMIT command after the last one, thereby wrapping all the commands into a single transaction. This ensures that either all the commands complete successfully, or no changes are applied.

If the commands themselves contain BEGIN, COMMIT, or ROLLBACK, this option will not have the desired effects. Also, if an individual command cannot be executed inside a transaction block, specifying this option will cause the whole transaction to fail.

-?

--help[=topic]

Show help about psql and exit. The optional topic parameter (defaulting to options) selects which part of psql is explained: commands describes psql‘s backslash commands; options describes the command-line options that can be passed to psql; and variables shows help about psql configuration variables.

Exit Status

psql returns 0 to the shell if it finished normally, 1 if a fatal error of its own occurs (e.g. out of memory, file not found), 2 if the connection to the server went bad and the session was not interactive, and 3 if an error occurred in a script and the variable ON_ERROR_STOP was set.

Usage

Connecting to a Database

psql is a regular PostgreSQL client application. In order to connect to a database you need to know the name of your target database, the host name and port number of the server, and what user name you want to connect as. psql can be told about those parameters via command line options, namely -d, -h, -p, and -U respectively. If an argument is found that does not belong to any option it will be interpreted as the database name (or the user name, if the database name is already given). Not all of these options are required; there are useful defaults. If you omit the host name, psql will connect via a Unix-domain socket to a server on the local host, or via TCP/IP to localhost on machines that don’t have Unix-domain sockets. The default port number is determined at compile time. Since the database server uses the same default, you will not have to specify the port in most cases. The default user name is your operating-system user name, as is the default database name. Note that you cannot just connect to any database under any user name. Your database administrator should have informed you about your access rights.

When the defaults aren’t quite right, you can save yourself some typing by setting the environment variables PGDATABASE, PGHOST, PGPORT and/or PGUSER to appropriate values. (For additional environment variables, see Section 34.14.) It is also convenient to have a ~/.pgpass file to avoid regularly having to type in passwords. See Section 34.15 for more information.

An alternative way to specify connection parameters is in a conninfo string or a URI, which is used instead of a database name. This mechanism give you very wide control over the connection. For example:

$ psql "service=myservice sslmode=require"
$ psql postgresql://dbmaster:5433/mydb?sslmode=require

This way you can also use LDAP for connection parameter lookup as described in Section 34.17. See Section 34.1.2 for more information on all the available connection options.

If the connection could not be made for any reason (e.g., insufficient privileges, server is not running on the targeted host, etc.), psql will return an error and terminate.

If both standard input and standard output are a terminal, then psql sets the client encoding to auto, which will detect the appropriate client encoding from the locale settings (LC_CTYPE environment variable on Unix systems). If this doesn’t work out as expected, the client encoding can be overridden using the environment variable PGCLIENTENCODING.

Entering SQL Commands

In normal operation, psql provides a prompt with the name of the database to which psql is currently connected, followed by the string =>. For example:

$ psql testdb
psql (11.8)
Type "help" for help.

testdb=>

At the prompt, the user can type in SQL commands. Ordinarily, input lines are sent to the server when a command-terminating semicolon is reached. An end of line does not terminate a command. Thus commands can be spread over several lines for clarity. If the command was sent and executed without error, the results of the command are displayed on the screen.

If untrusted users have access to a database that has not adopted a secure schema usage pattern, begin your session by removing publicly-writable schemas from search_path. One can add options=-csearch_path= to the connection string or issue SELECT pg_catalog.set_config('search_path', '', false) before other SQL commands. This consideration is not specific to psql; it applies to every interface for executing arbitrary SQL commands.

Whenever a command is executed, psql also polls for asynchronous notification events generated by LISTEN and NOTIFY.

While C-style block comments are passed to the server for processing and removal, SQL-standard comments are removed by psql.

Advanced Features

Variables

psql provides variable substitution features similar to common Unix command shells. Variables are simply name/value pairs, where the value can be any string of any length. The name must consist of letters (including non-Latin letters), digits, and underscores.

To set a variable, use the psql meta-command \set. For example,

testdb=> \set foo bar

sets the variable foo to the value bar. To retrieve the content of the variable, precede the name with a colon, for example:

testdb=> \echo :foo
bar

This works in both regular SQL commands and meta-commands; there is more detail in SQL Interpolation, below.

If you call \set without a second argument, the variable is set to an empty-string value. To unset (i.e., delete) a variable, use the command \unset. To show the values of all variables, call \set without any argument.

Note

The arguments of \set are subject to the same substitution rules as with other commands. Thus you can construct interesting references such as \set :foo 'something' and get soft links or variable variables of Perl or PHP fame, respectively. Unfortunately (or fortunately?), there is no way to do anything useful with these constructs. On the other hand, \set bar :foo is a perfectly valid way to copy a variable.

A number of these variables are treated specially by psql. They represent certain option settings that can be changed at run time by altering the value of the variable, or in some cases represent changeable state of psql. By convention, all specially treated variables’ names consist of all upper-case ASCII letters (and possibly digits and underscores). To ensure maximum compatibility in the future, avoid using such variable names for your own purposes.

Variables that control psql‘s behavior generally cannot be unset or set to invalid values. An \unset command is allowed but is interpreted as setting the variable to its default value. A \set command without a second argument is interpreted as setting the variable to on, for control variables that accept that value, and is rejected for others. Also, control variables that accept the values on and off will also accept other common spellings of Boolean values, such as true and false.

The specially treated variables are:

AUTOCOMMIT

When on (the default), each SQL command is automatically committed upon successful completion. To postpone commit in this mode, you must enter a BEGIN or START TRANSACTION SQL command. When off or unset, SQL commands are not committed until you explicitly issue COMMIT or END. The autocommit-off mode works by issuing an implicit BEGIN for you, just before any command that is not already in a transaction block and is not itself a BEGIN or other transaction-control command, nor a command that cannot be executed inside a transaction block (such as VACUUM).

Note

In autocommit-off mode, you must explicitly abandon any failed transaction by entering ABORT or ROLLBACK. Also keep in mind that if you exit the session without committing, your work will be lost.

Note

The autocommit-on mode is PostgreSQL‘s traditional behavior, but autocommit-off is closer to the SQL spec. If you prefer autocommit-off, you might wish to set it in the system-wide psqlrc file or your ~/.psqlrc file.

COMP_KEYWORD_CASE

Determines which letter case to use when completing an SQL key word. If set to lower or upper, the completed word will be in lower or upper case, respectively. If set to preserve-lower or preserve-upper (the default), the completed word will be in the case of the word already entered, but words being completed without anything entered will be in lower or upper case, respectively.

DBNAME

The name of the database you are currently connected to. This is set every time you connect to a database (including program start-up), but can be changed or unset.

ECHO

If set to all, all nonempty input lines are printed to standard output as they are read. (This does not apply to lines read interactively.) To select this behavior on program start-up, use the switch -a. If set to queries, psql prints each query to standard output as it is sent to the server. The switch to select this behavior is -e. If set to errors, then only failed queries are displayed on standard error output. The switch for this behavior is -b. If set to none (the default), then no queries are displayed.

ECHO_HIDDEN

When this variable is set to on and a backslash command queries the database, the query is first shown. This feature helps you to study PostgreSQL internals and provide similar functionality in your own programs. (To select this behavior on program start-up, use the switch -E.) If you set this variable to the value noexec, the queries are just shown but are not actually sent to the server and executed. The default value is off.

ENCODING

The current client character set encoding. This is set every time you connect to a database (including program start-up), and when you change the encoding with \encoding, but it can be changed or unset.

ERROR

true if the last SQL query failed, false if it succeeded. See also SQLSTATE.

FETCH_COUNT

If this variable is set to an integer value greater than zero, the results of SELECT queries are fetched and displayed in groups of that many rows, rather than the default behavior of collecting the entire result set before display. Therefore only a limited amount of memory is used, regardless of the size of the result set. Settings of 100 to 1000 are commonly used when enabling this feature. Keep in mind that when using this feature, a query might fail after having already displayed some rows.

Tip

Although you can use any output format with this feature, the default aligned format tends to look bad because each group of FETCH_COUNT rows will be formatted separately, leading to varying column widths across the row groups. The other output formats work better.

HISTCONTROL

If this variable is set to ignorespace, lines which begin with a space are not entered into the history list. If set to a value of ignoredups, lines matching the previous history line are not entered. A value of ignoreboth combines the two options. If set to none (the default), all lines read in interactive mode are saved on the history list.

Note

This feature was shamelessly plagiarized from Bash.

HISTFILE

The file name that will be used to store the history list. If unset, the file name is taken from the PSQL_HISTORY environment variable. If that is not set either, the default is ~/.psql_history, or %APPDATA%\postgresql\psql_history on Windows. For example, putting:

\set HISTFILE ~/.psql_history- :DBNAME

in ~/.psqlrc will cause psql to maintain a separate history for each database.

Note

This feature was shamelessly plagiarized from Bash.

HISTSIZE

The maximum number of commands to store in the command history (default 500). If set to a negative value, no limit is applied.

Note

This feature was shamelessly plagiarized from Bash.

HOST

The database server host you are currently connected to. This is set every time you connect to a database (including program start-up), but can be changed or unset.

IGNOREEOF

If set to 1 or less, sending an EOF character (usually Control+D) to an interactive session of psql will terminate the application. If set to a larger numeric value, that many consecutive EOF characters must be typed to make an interactive session terminate. If the variable is set to a non-numeric value, it is interpreted as 10. The default is 0.

Note

This feature was shamelessly plagiarized from Bash.

LASTOID

The value of the last affected OID, as returned from an INSERT or \lo_import command. This variable is only guaranteed to be valid until after the result of the next SQL command has been displayed.

LAST_ERROR_MESSAGE

LAST_ERROR_SQLSTATE

The primary error message and associated SQLSTATE code for the most recent failed query in the current psql session, or an empty string and 00000 if no error has occurred in the current session.

ON_ERROR_ROLLBACK

When set to on, if a statement in a transaction block generates an error, the error is ignored and the transaction continues. When set to interactive, such errors are only ignored in interactive sessions, and not when reading script files. When set to off (the default), a statement in a transaction block that generates an error aborts the entire transaction. The error rollback mode works by issuing an implicit SAVEPOINT for you, just before each command that is in a transaction block, and then rolling back to the savepoint if the command fails.

ON_ERROR_STOP

By default, command processing continues after an error. When this variable is set to on, processing will instead stop immediately. In interactive mode, psql will return to the command prompt; otherwise, psql will exit, returning error code 3 to distinguish this case from fatal error conditions, which are reported using error code 1. In either case, any currently running scripts (the top-level script, if any, and any other scripts which it may have in invoked) will be terminated immediately. If the top-level command string contained multiple SQL commands, processing will stop with the current command.

PORT

The database server port to which you are currently connected. This is set every time you connect to a database (including program start-up), but can be changed or unset.

PROMPT1

PROMPT2

PROMPT3

These specify what the prompts psql issues should look like. See Prompting below.

QUIET

Setting this variable to on is equivalent to the command line option -q. It is probably not too useful in interactive mode.

ROW_COUNT

The number of rows returned or affected by the last SQL query, or 0 if the query failed or did not report a row count.

SERVER_VERSION_NAME

SERVER_VERSION_NUM

The server’s version number as a string, for example 9.6.2, 10.1 or 11beta1, and in numeric form, for example 90602 or 100001. These are set every time you connect to a database (including program start-up), but can be changed or unset.

SHOW_CONTEXT

This variable can be set to the values never, errors, or always to control whether CONTEXT fields are displayed in messages from the server. The default is errors (meaning that context will be shown in error messages, but not in notice or warning messages). This setting has no effect when VERBOSITY is set to terse. (See also \errverbose, for use when you want a verbose version of the error you just got.)

SINGLELINE

Setting this variable to on is equivalent to the command line option -S.

SINGLESTEP

Setting this variable to on is equivalent to the command line option -s.

SQLSTATE

The error code (see Appendix A) associated with the last SQL query’s failure, or 00000 if it succeeded.

USER

The database user you are currently connected as. This is set every time you connect to a database (including program start-up), but can be changed or unset.

VERBOSITY

This variable can be set to the values default, verbose, or terse to control the verbosity of error reports. (See also \errverbose, for use when you want a verbose version of the error you just got.)

VERSION

VERSION_NAME

VERSION_NUM

These variables are set at program start-up to reflect psql‘s version, respectively as a verbose string, a short string (e.g., 9.6.2, 10.1, or 11beta1), and a number (e.g., 90602 or 100001). They can be changed or unset.

SQL Interpolation

A key feature of psql variables is that you can substitute (interpolate) them into regular SQL statements, as well as the arguments of meta-commands. Furthermore, psql provides facilities for ensuring that variable values used as SQL literals and identifiers are properly quoted. The syntax for interpolating a value without any quoting is to prepend the variable name with a colon (:). For example,

testdb=> \set foo 'my_table'
testdb=> SELECT * FROM :foo;

would query the table my_table. Note that this may be unsafe: the value of the variable is copied literally, so it can contain unbalanced quotes, or even backslash commands. You must make sure that it makes sense where you put it.

When a value is to be used as an SQL literal or identifier, it is safest to arrange for it to be quoted. To quote the value of a variable as an SQL literal, write a colon followed by the variable name in single quotes. To quote the value as an SQL identifier, write a colon followed by the variable name in double quotes. These constructs deal correctly with quotes and other special characters embedded within the variable value. The previous example would be more safely written this way:

testdb=> \set foo 'my_table'
testdb=> SELECT * FROM :"foo";

Variable interpolation will not be performed within quoted SQL literals and identifiers. Therefore, a construction such as ':foo' doesn’t work to produce a quoted literal from a variable’s value (and it would be unsafe if it did work, since it wouldn’t correctly handle quotes embedded in the value).

One example use of this mechanism is to copy the contents of a file into a table column. First load the file into a variable and then interpolate the variable’s value as a quoted string:

testdb=> \set content `cat my_file.txt`
testdb=> INSERT INTO my_table VALUES (:'content');

(Note that this still won’t work if my_file.txt contains NUL bytes. psql does not support embedded NUL bytes in variable values.)

Since colons can legally appear in SQL commands, an apparent attempt at interpolation (that is, :name, :'name', or :"name") is not replaced unless the named variable is currently set. In any case, you can escape a colon with a backslash to protect it from substitution.

The :{?name} special syntax returns TRUE or FALSE depending on whether the variable exists or not, and is thus always substituted, unless the colon is backslash-escaped.

The colon syntax for variables is standard SQL for embedded query languages, such as ECPG. The colon syntaxes for array slices and type casts are PostgreSQL extensions, which can sometimes conflict with the standard usage. The colon-quote syntax for escaping a variable’s value as an SQL literal or identifier is a psql extension.

Prompting

The prompts psql issues can be customized to your preference. The three variables PROMPT1, PROMPT2, and PROMPT3 contain strings and special escape sequences that describe the appearance of the prompt. Prompt 1 is the normal prompt that is issued when psql requests a new command. Prompt 2 is issued when more input is expected during command entry, for example because the command was not terminated with a semicolon or a quote was not closed. Prompt 3 is issued when you are running an SQL COPY FROM STDIN command and you need to type in a row value on the terminal.

The value of the selected prompt variable is printed literally, except where a percent sign (%) is encountered. Depending on the next character, certain other text is substituted instead. Defined substitutions are:

%M

The full host name (with domain name) of the database server, or [local] if the connection is over a Unix domain socket, or [local:/dir/name], if the Unix domain socket is not at the compiled in default location.

%m

The host name of the database server, truncated at the first dot, or [local] if the connection is over a Unix domain socket.

%>

The port number at which the database server is listening.

%n

The database session user name. (The expansion of this value might change during a database session as the result of the command SET SESSION AUTHORIZATION.)

%/

The name of the current database.

%~

Like %/, but the output is ~ (tilde) if the database is your default database.

%#

If the session user is a database superuser, then a #, otherwise a >. (The expansion of this value might change during a database session as the result of the command SET SESSION AUTHORIZATION.)

%p

The process ID of the backend currently connected to.

%R

In prompt 1 normally =, but @ if the session is in an inactive branch of a conditional block, or ^ if in single-line mode, or ! if the session is disconnected from the database (which can happen if \connect fails). In prompt 2 %R is replaced by a character that depends on why psql expects more input: - if the command simply wasn’t terminated yet, but * if there is an unfinished /* ... */ comment, a single quote if there is an unfinished quoted string, a double quote if there is an unfinished quoted identifier, a dollar sign if there is an unfinished dollar-quoted string, or ( if there is an unmatched left parenthesis. In prompt 3 %R doesn’t produce anything.

%x

Transaction status: an empty string when not in a transaction block, or * when in a transaction block, or ! when in a failed transaction block, or ? when the transaction state is indeterminate (for example, because there is no connection).

%l

The line number inside the current statement, starting from 1.

%digits

The character with the indicated octal code is substituted.

%:name:

The value of the psql variable name. See the section Variables for details.

%`command`

The output of command, similar to ordinary back-tick substitution.

%[%]

Prompts can contain terminal control characters which, for example, change the color, background, or style of the prompt text, or change the title of the terminal window. In order for the line editing features of Readline to work properly, these non-printing control characters must be designated as invisible by surrounding them with %[ and %]. Multiple pairs of these can occur within the prompt. For example:

testdb=> \set PROMPT1 '%[%033[1;33;40m%]%n@%/%R%[%033[0m%]%# '

results in a boldfaced (1;) yellow-on-black (33;40) prompt on VT100-compatible, color-capable terminals.

To insert a percent sign into your prompt, write %%. The default prompts are '%/%R%# ' for prompts 1 and 2, and '>> ' for prompt 3.

Note

This feature was shamelessly plagiarized from tcsh.

Command-Line Editing

psql supports the Readline library for convenient line editing and retrieval. The command history is automatically saved when psql exits and is reloaded when psql starts up. Tab-completion is also supported, although the completion logic makes no claim to be an SQL parser. The queries generated by tab-completion can also interfere with other SQL commands, e.g. SET TRANSACTION ISOLATION LEVEL. If for some reason you do not like the tab completion, you can turn it off by putting this in a file named .inputrc in your home directory:

$if psql
set disable-completion on
$endif

(This is not a psql but a Readline feature. Read its documentation for further details.)

Environment

COLUMNS

If \pset columns is zero, controls the width for the wrapped format and width for determining if wide output requires the pager or should be switched to the vertical format in expanded auto mode.

PGDATABASE

PGHOST

PGPORT

PGUSER

Default connection parameters (see Section 34.14).

PSQL_EDITOR

EDITOR

VISUAL

Editor used by the \e, \ef, and \ev commands. These variables are examined in the order listed; the first that is set is used. If none of them is set, the default is to use vi on Unix systems or notepad.exe on Windows systems.

PSQL_EDITOR_LINENUMBER_ARG

When \e, \ef, or \ev is used with a line number argument, this variable specifies the command-line argument used to pass the starting line number to the user’s editor. For editors such as Emacs or vi, this is a plus sign. Include a trailing space in the value of the variable if there needs to be space between the option name and the line number. Examples:

PSQL_EDITOR_LINENUMBER_ARG='+'
PSQL_EDITOR_LINENUMBER_ARG='--line '

The default is + on Unix systems (corresponding to the default editor vi, and useful for many other common editors); but there is no default on Windows systems.

PSQL_HISTORY

Alternative location for the command history file. Tilde (~) expansion is performed.

PSQL_PAGER

PAGER

If a query’s results do not fit on the screen, they are piped through this command. Typical values are more or less. Use of the pager can be disabled by setting PSQL_PAGER or PAGER to an empty string, or by adjusting the pager-related options of the \pset command. These variables are examined in the order listed; the first that is set is used. If none of them is set, the default is to use more on most platforms, but less on Cygwin.

PSQLRC

Alternative location of the user’s .psqlrc file. Tilde (~) expansion is performed.

SHELL

Command executed by the \! command.

TMPDIR

Directory for storing temporary files. The default is /tmp.

This utility, like most other PostgreSQL utilities, also uses the environment variables supported by libpq (see Section 34.14).

Files

psqlrc and ~/.psqlrc

Unless it is passed an -X option, psql attempts to read and execute commands from the system-wide startup file (psqlrc) and then the user’s personal startup file (~/.psqlrc), after connecting to the database but before accepting normal commands. These files can be used to set up the client and/or the server to taste, typically with \set and SET commands.

The system-wide startup file is named psqlrc and is sought in the installation’s system configuration directory, which is most reliably identified by running pg_config --sysconfdir. By default this directory will be ../etc/ relative to the directory containing the PostgreSQL executables. The name of this directory can be set explicitly via the PGSYSCONFDIR environment variable.

The user’s personal startup file is named .psqlrc and is sought in the invoking user’s home directory. On Windows, which lacks such a concept, the personal startup file is named %APPDATA%\postgresql\psqlrc.conf. The location of the user’s startup file can be set explicitly via the PSQLRC environment variable.

Both the system-wide startup file and the user’s personal startup file can be made psql-version-specific by appending a dash and the PostgreSQL major or minor release number to the file name, for example ~/.psqlrc-9.2 or ~/.psqlrc-9.2.5. The most specific version-matching file will be read in preference to a non-version-specific file.

.psql_history

The command-line history is stored in the file ~/.psql_history, or %APPDATA%\postgresql\psql_history on Windows.

The location of the history file can be set explicitly via the HISTFILE psql variable or the PSQL_HISTORY environment variable.

Notes

  • psql works best with servers of the same or an older major version. Backslash commands are particularly likely to fail if the server is of a newer version than psql itself. However, backslash commands of the \d family should work with servers of versions back to 7.4, though not necessarily with servers newer than psql itself. The general functionality of running SQL commands and displaying query results should also work with servers of a newer major version, but this cannot be guaranteed in all cases.

    If you want to use psql to connect to several servers of different major versions, it is recommended that you use the newest version of psql. Alternatively, you can keep around a copy of psql from each major version and be sure to use the version that matches the respective server. But in practice, this additional complication should not be necessary.

  • Before PostgreSQL 9.6, the -c option implied -X (--no-psqlrc); this is no longer the case.

  • Before PostgreSQL 8.4, psql allowed the first argument of a single-letter backslash command to start directly after the command, without intervening whitespace. Now, some whitespace is required.

Notes for Windows Users

psql is built as a console application. Since the Windows console windows use a different encoding than the rest of the system, you must take special care when using 8-bit characters within psql. If psql detects a problematic console code page, it will warn you at startup. To change the console code page, two things are necessary:

  • Set the code page by entering cmd.exe /c chcp 1252. (1252 is a code page that is appropriate for German; replace it with your value.) If you are using Cygwin, you can put this command in /etc/profile.

  • Set the console font to Lucida Console, because the raster font does not work with the ANSI code page.

Examples

The first example shows how to spread a command over several lines of input. Notice the changing prompt:

testdb=> CREATE TABLE my_table (
testdb(>  first integer not null default 0,
testdb(>  second text)
testdb-> ;
CREATE TABLE

Now look at the table definition again:

testdb=> \d my_table
              Table "public.my_table"
 Column |  Type   | Collation | Nullable | Default
--------+---------+-----------+----------+---------
 first  | integer |           | not null | 0
 second | text    |           |          | 

Now we change the prompt to something more interesting:

testdb=> \set PROMPT1 '%n@%m %~%R%# '
peter@localhost testdb=>

Let’s assume you have filled the table with data and want to take a look at it:

peter@localhost testdb=> SELECT * FROM my_table;
 first | second
-------+--------
     1 | one
     2 | two
     3 | three
     4 | four
(4 rows)

You can display tables in different ways by using the \pset command:

peter@localhost testdb=> \pset border 2
Border style is 2.
peter@localhost testdb=> SELECT * FROM my_table;
+-------+--------+
| first | second |
+-------+--------+
|     1 | one    |
|     2 | two    |
|     3 | three  |
|     4 | four   |
+-------+--------+
(4 rows)

peter@localhost testdb=> \pset border 0
Border style is 0.
peter@localhost testdb=> SELECT * FROM my_table;
first second
----- ------
    1 one
    2 two
    3 three
    4 four
(4 rows)

peter@localhost testdb=> \pset border 1
Border style is 1.
peter@localhost testdb=> \pset format unaligned
Output format is unaligned.
peter@localhost testdb=> \pset fieldsep ","
Field separator is ",".
peter@localhost testdb=> \pset tuples_only
Showing only tuples.
peter@localhost testdb=> SELECT second, first FROM my_table;
one,1
two,2
three,3
four,4

Alternatively, use the short commands:

peter@localhost testdb=> \a \t \x
Output format is aligned.
Tuples only is off.
Expanded display is on.
peter@localhost testdb=> SELECT * FROM my_table;
-[ RECORD 1 ]-
first  | 1
second | one
-[ RECORD 2 ]-
first  | 2
second | two
-[ RECORD 3 ]-
first  | 3
second | three
-[ RECORD 4 ]-
first  | 4
second | four

When suitable, query results can be shown in a crosstab representation with the \crosstabview command:

testdb=> SELECT first, second, first > 2 AS gt2 FROM my_table;
 first | second | gt2 
-------+--------+-----
     1 | one    | f
     2 | two    | f
     3 | three  | t
     4 | four   | t
(4 rows)

testdb=> \crosstabview first second
 first | one | two | three | four 
-------+-----+-----+-------+------
     1 | f   |     |       | 
     2 |     | f   |       | 
     3 |     |     | t     | 
     4 |     |     |       | t
(4 rows)

This second example shows a multiplication table with rows sorted in reverse numerical order and columns with an independent, ascending numerical order.

testdb=> SELECT t1.first as "A", t2.first+100 AS "B", t1.first*(t2.first+100) as "AxB",
testdb(> row_number() over(order by t2.first) AS ord
testdb(> FROM my_table t1 CROSS JOIN my_table t2 ORDER BY 1 DESC
testdb(> \crosstabview "A" "B" "AxB" ord
 A | 101 | 102 | 103 | 104 
---+-----+-----+-----+-----
 4 | 404 | 408 | 412 | 416
 3 | 303 | 306 | 309 | 312
 2 | 202 | 204 | 206 | 208
 1 | 101 | 102 | 103 | 104
(4 rows)

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