CALL
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## CALL

CALL — invoke a procedure

## Synopsis

    CALL name ( [ argument ] [, ...] )

## Description

`CALL` executes a procedure.

If the procedure has any output parameters, then a result row will be returned, containing the values of those parameters.

## Parameters

`name`

  The name (optionally schema-qualified) of the procedure.

`argument`

  An argument expression for the procedure call.

  Arguments can include parameter names, using the syntax ``name` => `value``. This works the same as in ordinary function calls; see Section 4.3 for details.

  Arguments must be supplied for all procedure parameters that lack defaults, including `OUT` parameters. However, arguments matching `OUT` parameters are not evaluated, so it's customary to just write `NULL` for them. (Writing something else for an `OUT` parameter might cause compatibility problems with future PostgreSQL versions.)

## Notes

The user must have `EXECUTE` privilege on the procedure in order to be allowed to invoke it.

To call a function (not a procedure), use `SELECT` instead.

If `CALL` is executed in a transaction block, then the called procedure cannot execute transaction control statements. Transaction control statements are only allowed if `CALL` is executed in its own transaction.

PL/pgSQL handles output parameters in `CALL` commands differently; see Section 45.6.3.

## Examples

    CALL do_db_maintenance();

## Compatibility

`CALL` conforms to the SQL standard, except for the handling of output parameters. The standard says that users should write variables to receive the values of output parameters.

## See Also

CREATE PROCEDURE

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