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\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.

\bind [parameter ] ...#

Sets query parameters for the next query execution, with the specified parameters passed for any parameter placeholders ($1 etc.).

Example:

INSERT INTO tbl1 VALUES ($1, $2) \bind 'first value' 'second value' \g

This also works for query-execution commands besides\g, such as\gx and\gset.

This command causes the extended query protocol (seeSection 53.1.2) to be used, unlike normalpsql operation, which uses the simple query protocol. So this command can be useful to test the extended query protocol from psql. (The extended query protocol is used even if the query has no parameters and this command specifies zero parameters.) This command affects only the next query executed; all subsequent queries will use the simple query protocol by default.

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

Establishes a new connection to aPostgres Pro server. The connection parameters to use can be specified either using a positional syntax (one or more of database name, user, host, and port), or using aconninfo connection string as detailed inSection 32.1.1. If no arguments are given, a new connection is made using the same parameters as before.

Specifying any ofdbname,username,host orport as- is equivalent to omitting that parameter.

The new connection can re-use connection parameters from the previous connection; not only database name, user, host, and port, but other settings such assslmode. By default, parameters are re-used in the positional syntax, but not when aconninfo string is given. Passing a first argument of-reuse-previous=on or-reuse-previous=off overrides that default. If parameters are re-used, then any parameter not explicitly specified as a positional parameter or in theconninfo string is taken from the existing connection's parameters. An exception is that if thehost setting is changed from its previous value using the positional syntax, anyhostaddr setting present in the existing connection's parameters is dropped. Also, any password used for the existing connection will be re-used only if the user, host, and port settings are not changed. When the command neither specifies nor reuses a particular parameter, thelibpq default is used.

If the new connection is successfully made, the previous connection is closed. If the connection attempt fails (wrong user name, access denied, etc.), the previous connection will be kept ifpsql is in interactive mode. But when executing a non-interactive script, the old connection is closed and an error is reported. That may or may not terminate the script; if it does not, all database-accessing commands will fail until another\connect command is successfully executed. 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. Note that whenever a\connect command attempts to re-use parameters, the values re-used are those of the last successful connection, not of any failed attempts made subsequently. However, in the case of a non-interactive\connect failure, no parameters are allowed to be re-used later, since the script would likely be expecting the values from the failed\connect to be re-used.

Examples:

=> \c mydb myuser host.dom 6432=> \c service=foo=> \c "host=localhost port=5432 dbname=mydb connect_timeout=10 sslmode=disable"=> \c -reuse-previous=on sslmode=require    -- changes only sslmode=> \c postgresql://tom@localhost/mydb?application_name=myapp

\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 titletitle. (The name of this command derives from“caption”, as it was previously only used to set the caption in anHTML table.)

\cd [directory ]#

Changes the current working directory todirectory. 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 ) ] }from {'filename' | program'command' | stdin | pstdin } [ [ with ] (option [, ...] ) ] [ wherecondition ]
\copy {table [ (column_list ) ] | (query ) }to {'filename' | program'command' | stdout | pstdout } [ [ with ] (option [, ...] ) ]#

Performs a frontend (client) copy. This is an operation that runs anSQLCOPY 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.

Whenprogram is specified,command is executed bypsql and the data passed from or tocommand 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 reachesEOF. This option is useful for populating tables in-line within an SQL script file. For\copy ... to stdout, output is sent to the same place aspsql command output, and theCOPYcount command status is not printed (since it might be confused with a data row). To read/writepsql's standard input or output regardless of the current command source or\o option, writefrom pstdin orto pstdout.

The syntax of this command is similar to that of theSQLCOPY command. All options other than the data source/destination are as specified forCOPY. 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

Another way to obtain the same result as\copy ... to is to use theSQLCOPY ... TO STDOUT command and terminate it with\gfilename or\g |program. Unlike\copy, this method allows the command to span multiple lines; also, variable interpolation and backquote expansion can be used.

Tip

These operations are not as efficient as theSQLCOPY command with a file or program data source or destination, because all data must pass through the client/server connection. For large amounts of data theSQL command might be preferable. Also, because of this pass-through method,\copy ... from inCSV mode will erroneously treat a\. data value alone on a line as an end-of-input marker.

\copyright#

Shows the copyright and distribution terms ofPostgres Pro.

\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 bycolV becomes a vertical header and the output column identified bycolH 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 andcolH as column 2.colH must differ fromcolV. IfcolD is not specified, then there must be exactly three columns in the query result, and the column that is neithercolV norcolH is taken to becolD.

The vertical header, displayed as the leftmost column, contains the values found in columncolV, 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 columncolH, with duplicates removed. By default, these appear in the same order as in the query results. But if the optionalsortcolH argument is given, it identifies a column whose values must be integer numbers, and the values fromcolH will appear in the horizontal header sorted according to the correspondingsortcolH values.

Inside the crosstab grid, for each distinct valuex ofcolH and each distinct valuey ofcolV, the cell located at the intersection(x,y) contains the value of thecolD column in the query result row for which the value ofcolH isx and the value ofcolV isy. 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 thepattern, show all columns, their types, the tablespace (if not the default) and any special attributes such asNOT 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 inPatterns 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-defaultreplica identity setting and theaccess method name if the relation has an access method.

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

Note

If\d is used without apattern 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. Ifpattern is specified, only aggregates whose names match the pattern are shown. By default, only user-created objects are shown; supply a pattern or theS modifier to include system objects.

\dA[+] [pattern ]#

Lists access methods. Ifpattern 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.

\dAc[+] [access-method-pattern [input-type-pattern]]#

Lists operator classes (seeSection 36.16.1). Ifaccess-method-pattern is specified, only operator classes associated with access methods whose names match that pattern are listed. Ifinput-type-pattern is specified, only operator classes associated with input types whose names match that pattern are listed. If+ is appended to the command name, each operator class is listed with its associated operator family and owner.

\dAf[+] [access-method-pattern [input-type-pattern]]#

Lists operator families (seeSection 36.16.5). Ifaccess-method-pattern is specified, only operator families associated with access methods whose names match that pattern are listed. Ifinput-type-pattern is specified, only operator families associated with input types whose names match that pattern are listed. If+ is appended to the command name, each operator family is listed with its owner.

\dAo[+] [access-method-pattern [operator-family-pattern]]#

Lists operators associated with operator families (seeSection 36.16.2). Ifaccess-method-pattern is specified, only members of operator families associated with access methods whose names match that pattern are listed. Ifoperator-family-pattern is specified, only members of operator families whose names match that pattern are listed. If+ is appended to the command name, each operator is listed with its sort operator family (if it is an ordering operator).

\dAp[+] [access-method-pattern [operator-family-pattern]]#

Lists support functions associated with operator families (seeSection 36.16.3). Ifaccess-method-pattern is specified, only functions of operator families associated with access methods whose names match that pattern are listed. Ifoperator-family-pattern is specified, only functions of operator families whose names match that pattern are listed. If+ is appended to the command name, functions are displayed verbosely, with their actual parameter lists.

\db[+] [pattern ]#

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

\dconfig[+] [pattern ]#

Lists server configuration parameters and their values. Ifpattern is specified, only parameters whose names match the pattern are listed. Without apattern, only parameters that are set to non-default values are listed. (Use\dconfig * to see all parameters.) If+ is appended to the command name, each parameter is listed with its data type, context in which the parameter can be set, and access privileges (if non-default access privileges have been granted).

\dC[+] [pattern ]#

Lists type casts. Ifpattern 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 typeconstraint,operator class,operator family,rule, andtrigger. All other comments may be viewed by the respective backslash commands for those object types.

\dd displays descriptions for objects matching thepattern, 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 theS modifier to include system objects.

Descriptions for objects can be created with theCOMMENTSQL command.

\dD[S+] [pattern ]#

Lists domains. Ifpattern is specified, only domains whose names match the pattern are shown. By default, only user-created objects are shown; supply a pattern or theS 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. Ifpattern is specified, only entries whose role name or schema name matches the pattern are listed.

TheALTER DEFAULT PRIVILEGES command is used to set default access privileges. The meaning of the privilege display is explained inSection 5.8.

\dE[S+] [pattern ]
\di[S+] [pattern ]
\dm[S+] [pattern ]
\ds[S+] [pattern ]
\dt[S+] [pattern ]
\dv[S+] [pattern ]#

In this group of commands, the lettersE,i,m,s,t, andv 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,\dti lists tables and indexes. If+ is appended to the command name, each object is listed with its persistence status (permanent, temporary, or unlogged), physical size on disk, and associated description if any. Ifpattern is specified, only objects whose names match the pattern are listed. By default, only user-created objects are shown; supply a pattern or theS modifier to include system objects.

\des[+] [pattern ]#

Lists foreign servers (mnemonic:“external servers”). Ifpattern 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 access privileges, type, version, options, and description.

\det[+] [pattern ]#

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

\df[anptwS+] [pattern [arg_pattern ... ] ]#

Lists functions, together with their result data types, argument data types, and function types, which are classified as“agg” (aggregate),“normal”,“procedure”,“trigger”, or“window”. To display only functions of specific type(s), add the corresponding lettersa,n,p,t, orw to the command. Ifpattern is specified, only functions whose names match the pattern are shown. Any additional arguments are type-name patterns, which are matched to the type names of the first, second, and so on arguments of the function. (Matching functions can have more arguments than what you specify. To prevent that, write a dash- as the lastarg_pattern.) By default, only user-created objects are shown; supply a pattern or theS 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, internal name (for C and internal functions only), and description. Source code for a specific function can be seen using\sf.

\dF[+] [pattern ]#

Lists text search configurations. Ifpattern 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. Ifpattern 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. Ifpattern 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. Ifpattern 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 theS modifier to include system roles. Ifpattern 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. If+ is appended to the command name, each large object is listed with its associated permissions, if any.

\dL[S+] [pattern ]#

Lists procedural languages. Ifpattern is specified, only languages whose names match the pattern are listed. By default, only user-created languages are shown; supply theS 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). Ifpattern is specified, only schemas whose names match the pattern are listed. By default, only user-created objects are shown; supply a pattern or theS 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 [arg_pattern [arg_pattern ] ] ]#

Lists operators with their operand and result types. Ifpattern is specified, only operators whose names match the pattern are listed. If onearg_pattern is specified, only prefix operators whose right argument's type name matches that pattern are listed. If twoarg_patterns are specified, only binary operators whose argument type names match those patterns are listed. (Alternatively, write- for the unused argument of a unary operator.) By default, only user-created objects are shown; supply a pattern or theS 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. Ifpattern is specified, only collations whose names match the pattern are listed. By default, only user-created objects are shown; supply a pattern or theS 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[S] [pattern ]#

Lists tables, views and sequences with their associated access privileges. Ifpattern is specified, only tables, views and sequences whose names match the pattern are listed. By default only user-created objects are shown; supply a pattern or theS modifier to include system objects.

TheGRANT andREVOKE commands are used to set access privileges. The meaning of the privilege display is explained inSection 5.8.

\dP[itn+] [pattern ]#

Lists partitioned relations. Ifpattern is specified, only entries whose name matches the pattern are listed. The modifierst (tables) andi (indexes) can be appended to the command, filtering the kind of relations to list. By default, partitioned tables and indexes are listed.

If the modifiern (“nested”) is used, or a pattern is specified, then non-root partitioned relations are included, and a column is shown displaying the parent of each partitioned relation.

If+ is appended to the command name, the sum of the sizes of each relation's partitions is also displayed, along with the relation's description. Ifn is combined with+, two sizes are shown: one including the total size of directly-attached leaf partitions, and another showing the total size of all partitions, including indirectly attached sub-partitions.

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

Lists defined configuration settings. These settings can be role-specific, database-specific, or both.role-pattern anddatabase-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.

TheALTER ROLE andALTER DATABASE commands are used to define per-role and per-database configuration settings.

\drg[S] [pattern ]#

Lists information about each granted role membership, including assigned options (ADMIN,INHERIT and/orSET) and grantor. See theGRANT command for information about role memberships.

By default, only grants to user-created roles are shown; supply theS modifier to include system roles. Ifpattern is specified, only grants to those roles whose names match the pattern are listed.

\dRp[+] [pattern ]#

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

\dRs[+] [pattern ]#

Lists replication subscriptions. Ifpattern 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.

\duP [pattern ]#

Lists profiles. Ifpattern is specified, only those profiles whose names match the pattern are listed. This command is only available for superusers.

\dT[S+] [pattern ]#

Lists data types. Ifpattern 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 anenum type, and its associated permissions. By default, only user-created objects are shown; supply a pattern or theS 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 theS modifier to include system roles. Ifpattern 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. Ifpattern 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.

\dX [pattern ]#

Lists extended statistics. Ifpattern is specified, only those extended statistics whose names match the pattern are listed.

The status of each kind of extended statistics is shown in a column named after its statistic kind (e.g. Ndistinct).defined means that it was requested when creating the statistics, and NULL means it wasn't requested. You can usepg_stats_ext if you'd like to know whetherANALYZE was run and statistics are available to the planner.

\dy[+] [pattern ]#

Lists event triggers. Ifpattern 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]#

Iffilename is specified, the file is edited; after the editor exits, the file's content is copied into the current query buffer. If nofilename 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.

If you edit a file or the previous query, and you quit the editor without modifying the file, the query buffer is cleared. Otherwise, the new contents of the query buffer are re-parsed according to the normal rules ofpsql, 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 and removed from the query buffer. Whatever remains in the query buffer is redisplayed. 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

SeeEnvironment, below, for how to configure and customize your editor.

\echotext [ ... ]#

Prints the evaluated arguments to standard output, separated by spaces 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 (nor is the first argument).

Tip

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

\ef [function_description [line_number]]#

This command fetches and edits the definition of the named function or procedure, in the form of aCREATE OR REPLACE FUNCTION orCREATE OR REPLACE PROCEDURE command. Editing is done in the same way as for\edit. If you quit the editor without saving, the statement is discarded. If you save and exit the editor, the updated command is executed immediately if you added a semicolon to it. Otherwise it is redisplayed; 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 examplefoo(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 blankCREATE 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

SeeEnvironment, below, 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 thoughVERBOSITY were set toverbose andSHOW_CONTEXT were set toalways.

\ev [view_name [line_number]]#

This command fetches and edits the definition of the named view, in the form of aCREATE OR REPLACE VIEW command. Editing is done in the same way as for\edit. If you quit the editor without saving, the statement is discarded. If you save and exit the editor, the updated command is executed immediately if you added a semicolon to it. Otherwise it is redisplayed; type semicolon or\g to send it, or\r to cancel.

If no view is specified, a blankCREATE 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 [ (option=value [...]) ] [filename ]
\g [ (option=value [...]) ] [ |command ]#

Sends the current query buffer to the server for execution.

If parentheses appear after\g, they surround a space-separated list ofoption=value formatting-option clauses, which are interpreted in the same way as\psetoptionvalue commands, but take effect only for the duration of this query. In this list, spaces are not allowed around= signs, but are required between option clauses. If=value is omitted, the namedoption is changed in the same way as for\psetoption with no explicitvalue.

If afilename or|command 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 any arguments is essentially equivalent to a semicolon. With arguments,\g provides a“one-shot” alternative to the\o command, and additionally allows one-shot adjustments of the output formatting options normally set by\pset.

When the last argument begins with|, the entire remainder of the line is taken to be thecommand 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.

\gdesc#

Shows the description (that is, the column names and data types) of the result of the current query buffer. The query is not actually executed; however, if it contains some type of syntax error, that error will be reported in the normal way.

If the current query buffer is empty, the most recently sent query is described instead.

\getenvpsql_varenv_var#

Gets the value of the environment variableenv_var and assigns it to thepsql variablepsql_var. Ifenv_var is not defined in thepsql process's environment,psql_var is not changed. Example:

=>\getenv home HOME=>\echo :home/home/postgres

\gexec#

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

=>SELECT format('create index on my_table(%I)', attname)->FROM pg_attribute->WHERE attrelid = 'my_table'::regclass AND attnum > 0->ORDER BY attnum->\gexecCREATE INDEXCREATE INDEXCREATE INDEXCREATE 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 bepsql meta-commands nor containpsql variable references. If any individual query fails, execution of the remaining queries continues unlessON_ERROR_STOP is set. Execution of each query is subject toECHO processing. (SettingECHO toall orqueries 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 intopsql variables (seeVariables below). 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 :var2hello 10

If you specify aprefix, 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_var2hello 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 [ (option=value [...]) ] [filename ]
\gx [ (option=value [...]) ] [ |command ]#

\gx is equivalent to\g, except that it forces expanded output mode for this query, as ifexpanded=on were included in the list of\pset options. See also\x.

\h or\help[command ]#

Gives syntax help on the specifiedSQL command. Ifcommand is not specified, thenpsql will list all the commands for which syntax help is available. Ifcommand is an asterisk (*), then syntax help on allSQL 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 onHTML query output format. If theHTML 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\includefilename#

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

Iffilename 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 variableECHO toall.

\ifexpression
\elifexpression
\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 yieldstrue 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.

Theexpression 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, andtR will all be considered to betrue.

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, thenpsql 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 variablesSELECT    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_relativefilename#

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. Ifpattern 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_exportloidfilename#

Reads the large object withOIDloid from the database and writes it tofilename. Note that this is subtly different from the server functionlo_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'sOID.

\lo_importfilename [comment ]#

Stores the file into aPostgres Pro 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-sidelo_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 allPostgres Pro large objects currently stored in the database, along with any comments provided for them. If+ is appended to the command name, each large object is listed with its associated permissions, if any.

\lo_unlinkloid#

Deletes the large object withOIDloid from the database.

Tip

Use\lo_list to find out the large object'sOID.

\o or\out [filename ]
\o or\out [ |command ]#

Arranges to save future query results to the filefilename or pipe future results to the shell commandcommand. 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 thecommand 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 anALTER 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 variablename. 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 ofvalue vary depending on the selected option. For some options, omittingvalue causes the option to be toggled or unset, as described under the particular option. If no such behavior is mentioned, then omittingvalue 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#

Thevalue 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. InHTML format, this will translate directly into theborder=... 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 asborder = 2. Thelatex andlatex-longtable formats additionally allow a value of 3 to add dividing lines between data rows.

columns#

Sets the target width for thewrapped 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 variableCOLUMNS, or the detected screen width ifCOLUMNS is not set. In addition, ifcolumns is zero then thewrapped format only affects screen output. Ifcolumns is nonzero then file and pipe output is wrapped to that width as well.

csv_fieldsep#

Specifies the field separator to be used inCSV output format. If the separator character appears in a field's value, that field is output within double quotes, following standardCSV rules. The default is a comma.

expanded (orx)#

Ifvalue is specified it must be eitheron oroff, which will enable or disable expanded mode, orauto. Ifvalue 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-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#

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

format#

Sets the output format to one ofaligned,asciidoc,csv,html,latex,latex-longtable,troff-ms,unaligned, orwrapped. Unique abbreviations are allowed.

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

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. However, the field separator character is not treated specially if it appears in a column's value; soCSV format may be better suited for such purposes.

csv format writes column values separated by commas, applying the quoting rules described inRFC 4180. This output is compatible with the CSV format of the server'sCOPY command. A header line with column names is generated unless thetuples_only parameter ison. Titles and footers are not printed. Each row is terminated by the system-dependent end-of-line character, which is typically a single newline (\n) for Unix-like systems or a carriage return and newline sequence (\r\n) for Microsoft Windows. Field separator characters other than comma can be selected with\pset csv_fieldsep.

wrapped format is likealigned 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 thecolumns option. Note thatpsql will not attempt to wrap column header titles; therefore,wrapped format behaves the same asaligned if the total width needed for column headers exceeds the target.

Theasciidoc,html,latex,latex-longtable, andtroff-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 inHTML, but inLaTeX you must have a complete document wrapper. Thelatex format usesLaTeX'stabular environment. Thelatex-longtable format requires theLaTeXlongtable andbooktabs packages.

linestyle#

Sets the border line drawing style to one ofascii,old-ascii, orunicode. Unique abbreviations are allowed. (That would mean one letter is enough.) The default setting isascii. This option only affects thealigned andwrapped output formats.

ascii style uses plainASCII characters. Newlines in data are shown using a+ symbol in the right-hand margin. When thewrapped 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 plainASCII characters, using the formatting style used inPostgreSQL 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 theborder setting is greater than zero, thelinestyle option also determines the characters with which the border lines are drawn. PlainASCII 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#

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

pager#

Controls use of a pager program for query andpsql help output. When thepager option isoff, the pager program is not used. When thepager option ison, the pager is used when appropriate, i.e., when the output is to a terminal and will not fit on the screen. Thepager option can also be set toalways, which causes the pager to be used for all terminal output regardless of whether it fits on the screen.\pset pager without avalue toggles pager use on and off.

If the environment variablePSQL_PAGER orPAGER is set, output to be paged is piped to the specified program. Otherwise a platform-dependent default program (such asmore) is used.

When using the\watch command to execute a query repeatedly, the environment variablePSQL_WATCH_PAGER is used to find the pager program instead, on Unix systems. This is configured separately because it may confuse traditional pagers, but can be used to send output to tools that understandpsql's output format (such aspspg --stream).

pager_min_lines#

Ifpager_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 (orT)#

InHTML format, this specifies attributes to be placed inside thetable tag. This could for example becellpadding orbgcolor. Note that you probably don't want to specifyborder here, as that is already taken care of by\pset border. If novalue is given, the table attributes are unset.

Inlatex-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 (orC)#

Sets the table title for any subsequently printed tables. This can be used to give your output descriptive tags. If novalue is given, the title is unset.

tuples_only (ort)#

Ifvalue is specified it must be eitheron oroff which will enable or disable tuples-only mode. Ifvalue 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 theunicode line style to one ofsingle ordouble.

unicode_column_linestyle#

Sets the column drawing style for theunicode line style to one ofsingle ordouble.

unicode_header_linestyle#

Sets the header drawing style for theunicode line style to one ofsingle ordouble.

xheader_width#

Sets the maximum width of the header for expanded output to one offull (the default value),column,page, or aninteger value.

full: the expanded header is not truncated, and will be as wide as the widest output line.

column: truncate the header line to the width of the first column.

page: truncate the header line to the terminal width.

integer value: specify the exact maximum width of the header line.

Illustrations of how these different formats look can be seen inExamples, below.

Tip

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

\q or\quit#

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

\qechotext [ ... ]#

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 ]#

Printpsql's command line history tofilename. Iffilename is omitted, the history is written to the standard output (using the pager if appropriate). This command is not available ifpsql was built withoutReadline support.

\set [name [value [ ... ] ] ]#

Sets thepsql variablename tovalue, 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-setpsql variables.

Valid variable names can contain letters, digits, and underscores. SeeVariables below for details. Variable names are case-sensitive.

Certain variables are special, in that they controlpsql's behavior or are automatically set to reflect connection state. These variables are documented inVariables, below.

Note

This command is unrelated to theSQL commandSET.

\setenvname [value ]#

Sets the environment variablename tovalue, or if thevalue is not supplied, unsets the environment variable. Example:

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

\sf[+]function_description#

This command fetches and shows the definition of the named function or procedure, in the form of aCREATE OR REPLACE FUNCTION orCREATE OR REPLACE PROCEDURE 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 examplefoo(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 aCREATE 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.

\Ttable_options#

Specifies attributes to be placed within thetable tag inHTML output format. This command is equivalent to\pset tableattrtable_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.

\unsetname#

Unsets (deletes) thepsql variablename.

Most variables that controlpsql's behavior cannot be unset; instead, an\unset command is interpreted as setting them to their default values. SeeVariables below.

\w or\writefilename
\w or\write|command#

Writes the current query buffer to the filefilename or pipes it to the shell commandcommand. 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 thecommand 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.

\warntext [ ... ]#

This command is identical to\echo except that the output will be written topsql's standard error channel, rather than standard output.

\watch [ i[nterval]=seconds ] [ c[ount]=times ] [ m[in_rows]=rows ] [seconds ]#

Repeatedly execute the current query buffer (as\g does) until interrupted, or the query fails, or the execution count limit (if given) is reached, or the query no longer returns the minimum number of rows. Wait the specified number of seconds (default 2) between executions. For backwards compatibility,seconds can be specified with or without aninterval= prefix. 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[S] [pattern ]#

Lists tables, views and sequences with their associated access privileges. If apattern is specified, only tables, views and sequences whose names match the pattern are listed. By default only user-created objects are shown; supply a pattern or theS modifier to include system objects.

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 commandcommand.

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 optionaltopic parameter (defaulting tocommands) selects which part ofpsql is explained:commands describespsql's backslash commands;options describes the command-line options that can be passed topsql; andvariables shows help aboutpsql configuration variables.

\;#

Backslash-semicolon is not a meta-command in the same way as the preceding commands; rather, it simply causes a semicolon to be added to the query buffer without any further processing.

Normally,psql will dispatch an SQL command to the server as soon as it reaches the command-ending semicolon, even if more input remains on the current line. Thus for example entering

select 1; select 2; select 3;

will result in the three SQL commands being individually sent to the server, with each one's results being displayed before continuing to the next command. However, a semicolon entered as\; will not trigger command processing, so that the command before it and the one after are effectively combined and sent to the server in one request. So for example

select 1\; select 2\; select 3;

results in sending the three SQL commands to the server in a single request, when the non-backslashed semicolon is reached. The server executes such a request as a single transaction, unless there are explicitBEGIN/COMMIT commands included in the string to divide it into multiple transactions. (SeeSection 53.2.2.1 for more details about how the server handles multi-query strings.)

Patterns#

The various\d commands accept apattern 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 namedfoo. 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 namedFOO"BAR (notfoo"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 namedfooFOObar.

Whenever thepattern 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 bevisible 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 withint. But within double quotes,* and? lose these special meanings and are just matched literally.

A relation 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 includesbar that are in schemas whose schema name starts withfoo. 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. A relation pattern that contains two dots (.) is interpreted as a database name followed by a schema name pattern followed by an object name pattern. The database name portion will not be treated as a pattern and must match the name of the currently connected database, else an error will be raised.

A schema pattern that contains a dot (.) is interpreted as a database name followed by a schema name pattern. For example,\dn mydb.*foo* displays all schemas whose schema name includesfoo. The database name portion will not be treated as a pattern and must match the name of the currently connected database, else an error will be raised.

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 inSection 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+|) forR*, or(R|) forR?.$ 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).

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 thepsql meta-command\set. For example,

testdb=>\set foo bar

sets the variablefoo to the valuebar. To retrieve the content of the variable, precede the name with a colon, for example:

testdb=>\echo :foobar

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

A number of these variables are treated specially bypsql. 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 ofpsql. 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 controlpsql'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 toon, for control variables that accept that value, and is rejected for others. Also, control variables that accept the valueson andoff will also accept other common spellings of Boolean values, such astrue andfalse.

The specially treated variables are:

SQL Interpolation#

A key feature ofpsql variables is that you can substitute (“interpolate”) them into regularSQL 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 tablemy_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 quotedSQL 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 ifmy_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 standardSQL for embedded query languages, such asECPG. The colon syntaxes for array slices and type casts arePostgres Pro 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 apsql extension.

Prompting#

The promptspsql issues can be customized to your preference. The three variablesPROMPT1,PROMPT2, andPROMPT3 contain strings and special escape sequences that describe the appearance of the prompt. Prompt 1 is the normal prompt that is issued whenpsql 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 anSQLCOPY 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:

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

Command-Line Editing#

psql uses theReadline orlibedit library, if available, for convenient line editing and retrieval. The command history is automatically saved whenpsql exits and is reloaded whenpsql 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, typingins and pressing TAB will fill ininsert into. Then, typing a few characters of a table or schema name and pressingTAB 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 pressTAB 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, afterBEGIN it will be too late to issueSET 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:

$if psqlset disable-completion on$endif

(This is not apsql but aReadline feature. Read its documentation for further details.)

The-n (--no-readline) command line option can also be useful to disable use ofReadline for a single run ofpsql. 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 containsTAB characters.