DROP FUNCTION name ( [type [, ...]] )
The name of an existing function.
The type of function parameters.
Message returned if the command completes successfully.
This message is given if the function specified does not exist into database.
DROP FUNCTION will remove references to an existing C function. To execute this command the user must be the owner of the function. The input argument types to the function must be specified, as only the function with the given name and argument types will be removed.
Refer to the CREATE FUNCTION statement to create aggregate functions.
This command removes the square root function:
DROP FUNCTION sqrt(int4);
No checks are made to ensure that types, operators or access methods that rely on the function have been removed first.
DROP FUNCTION statement is a PostgreSQL language extension.
The SQL/PSM DROP FUNCTION statement has the following syntax:
DROP [ SPECIFIC ] FUNCTION name { RESTRICT | CASCADE }