ALTER EVENT Statement EVENT  event_name [ON SCHEDULE  schedule ] [ON COMPLETION [NOT] PRESERVE] [RENAME TO  new_event_name ] [ENABLE | DISABLE | DISABLE ON SLAVE] [COMMENT ’ string ’] [DO  event_body ] mysql>  ALTER EVENT no_such_event  > ON SCHEDULE  > EVERY ’2:3’ DAY_HOUR; ERROR 1517 (HY000): Unknown event ’no_such_event’ CREATE EVENT myevent ON SCHEDULE EVERY 6 HOUR COMMENT ’A sample comment.’ DO UPDATE myschema.mytable SET mycol = mycol + 1; ALTER EVENT myevent ON SCHEDULE EVERY 12 HOUR STARTS CURRENT_TIMESTAMP + INTERVAL 4 HOUR; ALTER EVENT myevent ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 1 DAY DO TRUNCATE TABLE myschema.mytable; ALTER EVENT myevent DISABLE; The  ON SCHEDULE  clause may use expressions involving built-in MySQL functions and user variables to obtain any of the  timestamp  or  interval  values which it contains. You cannot use stored routines or loadable functions in such expressions, and you cannot use any table references; however, you can use SELECT FROM DUAL . This is true for both  ALTER EVENT  and  CREATE EVENT  statements. References to To disable  myevent , use this  ALTER EVENT  statement: Specify the options in an  ALTER EVENT  statement only for those characteristics that you want to change; omitted options keep their existing values. This includes any default values for  CREATE EVENT  such as ENABLE . It is possible to change multiple characteristics of an event in a single statement. This example changes the SQL statement executed by  myevent  to one that deletes all records from  mytable ; it also changes the schedule for the event such that it executes once, one day after this  ALTER EVENT  statement is run. The following statement changes the schedule for  myevent  from once every six hours starting immediately to once every twelve hours, starting four hours from the time the statement is run: In each of the following examples, assume that the event named  myevent  is defined as shown here: ALTER EVENT  works only with an existing event: Any user can alter an event defined on a database for which that user has the  EVENT  privilege. When a user executes a successful  ALTER EVENT  statement, that user becomes the definer for the affected event. The  ALTER EVENT  statement changes one or more of the characteristics of an existing event without the need to drop and recreate it. The syntax for each of the  DEFINER ,  ON SCHEDULE ,  ON COMPLETION , COMMENT ,  ENABLE  /  DISABLE , and  DO  clauses is exactly the same as when used with  CREATE EVENT . (See Section 13.1.13, “CREATE EVENT Statement” .) 2476