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 may exist with the same name and different argument lists.
The name (optionally schema-qualified) of an existing function.
The data type of an argument of the function.
Automatically drop objects that depend on the function (such as operators or triggers).
Refuse to drop the function if any objects depend on it. This is the default.
A DROP FUNCTION statement is defined in the SQL standard, but it is not compatible with this command.