CALL — invoke a procedure
CALLname( [argument] [, ...] )
CALL executes a procedure.
If the procedure has any output parameters, then a result row will be returned, containing the values of those parameters.
nameThe name (optionally schema-qualified) of the procedure.
argumentAn argument expression for the procedure call.
Arguments can include parameter names, using the syntax
name => value
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.)
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 44.6.3.
CALL do_db_maintenance();
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.