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DROP FUNCTION [IF EXISTS]function_name

This statement drops the loadable function namedfunction_name. (DROP FUNCTION is also used to drop stored functions; seeSection 15.1.29, “DROP PROCEDURE and DROP FUNCTION Statements”.)

DROP FUNCTION is the complement ofCREATE FUNCTION. It requires theDELETE privilege for themysql system schema because it removes the row from themysql.func system table that registers the function.

DROP FUNCTION also removes the function from the Performance Schemauser_defined_functions table that provides runtime information about installed loadable functions. SeeSection 29.12.22.11, “The user_defined_functions Table”.

During the normal startup sequence, the server loads functions registered in themysql.func table. BecauseDROP FUNCTION removes themysql.func row for the dropped function, the server does not load the function during subsequent restarts.

DROP FUNCTION cannot be used to drop a loadable function that is installed automatically by components or plugins rather than by usingCREATE FUNCTION. Such a function is also dropped automatically, when the component or plugin that installed it is uninstalled.