MySQL 9.5 Reference Manual Including MySQL NDB Cluster 9.5
      The CREATE FUNCTION statement is
      used to create stored functions and loadable functions:
    
For information about creating stored functions, see Section 15.1.21, “CREATE PROCEDURE and CREATE FUNCTION Statements”.
For information about creating loadable functions, see Section 15.7.4.1, “CREATE FUNCTION Statement for Loadable Functions”.