NAME

       DROP_FUNCTION - remove a function

SYNOPSIS

       DROP FUNCTION [ IF EXISTS ] name [ ( [ [ argmode ] [ argname ] argtype [, ...] ] ) ] [, ...]
           [ CASCADE | RESTRICT ]

DESCRIPTION

       DROP FUNCTION removes the definition of an existing function. To execute this command the
       user must be the owner of the function. The argument types to the function must be
       specified, since several different functions can exist with the same name and different
       argument lists.

PARAMETERS

       IF EXISTS
           Do not throw an error if the function does not exist. A notice is issued in this case.

       name
           The name (optionally schema-qualified) of an existing function. If no argument list is
           specified, the name must be unique in its schema.

       argmode
           The mode of an argument: IN, OUT, INOUT, or VARIADIC. If omitted, the default is IN.
           Note that DROP FUNCTION does not actually pay any attention to OUT arguments, since
           only the input arguments are needed to determine the function's identity. So it is
           sufficient to list the IN, INOUT, and VARIADIC arguments.

       argname
           The name of an argument. Note that DROP FUNCTION does not actually pay any attention
           to argument names, since only the argument data types are needed to determine the
           function's identity.

       argtype
           The data type(s) of the function's arguments (optionally schema-qualified), if any.

       CASCADE
           Automatically drop objects that depend on the function (such as operators or
           triggers), and in turn all objects that depend on those objects (see Section 5.14).

       RESTRICT
           Refuse to drop the function if any objects depend on it. This is the default.

EXAMPLES

       This command removes the square root function:

           DROP FUNCTION sqrt(integer);

       Drop multiple functions in one command:

           DROP FUNCTION sqrt(integer), sqrt(bigint);

       If the function name is unique in its schema, it can be referred to without an argument
       list:

           DROP FUNCTION update_employee_salaries;

       Note that this is different from

           DROP FUNCTION update_employee_salaries();

       which refers to a function with zero arguments, whereas the first variant can refer to a
       function with any number of arguments, including zero, as long as the name is unique.

COMPATIBILITY

       This command conforms to the SQL standard, with these PostgreSQL extensions:

       •   The standard only allows one function to be dropped per command.

       •   The IF EXISTS option

       •   The ability to specify argument modes and names

SEE ALSO

       CREATE FUNCTION (CREATE_FUNCTION(7)), ALTER FUNCTION (ALTER_FUNCTION(7)), DROP PROCEDURE
       (DROP_PROCEDURE(7)), DROP ROUTINE (DROP_ROUTINE(7))