DROP FUNCTION [IF EXISTS] function_name
This statement drops the loadable function named
FUNCTION is also used to drop stored functions; see
Section 13.1.29, “DROP PROCEDURE and DROP FUNCTION Statements”.)
FUNCTION is the complement of
FUNCTION. It requires the
DELETE privilege for the
mysql system schema because it removes the
row from the
mysql.func system table that
registers the function.
FUNCTION also removes the function from the
user_defined_functions table that
provides runtime information about installed loadable functions.
Section 22.214.171.124, “The user_defined_functions Table”.
During the normal startup sequence, the server loads functions
registered in the
mysql.func table. Because
FUNCTION removes the
for the dropped function, the server does not load the function
during subsequent restarts.
FUNCTION cannot be used to drop a loadable function
that is installed automatically by components or plugins rather
than by using
FUNCTION. Such a function is also dropped
automatically, when the component or plugin that installed it is
To upgrade the shared library associated with a loadable
function, issue a
FUNCTION statement, upgrade the shared library, and
then issue a
FUNCTION statement. If you upgrade the shared
library first and then use
FUNCTION, the server may unexpectedly shut down.