The Ultimate Guide to High Availability with MariaDB

CREATE EVENT

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Syntax:

CREATE 
    [DEFINER = { user | CURRENT_USER }]
    EVENT 
    [IF NOT EXISTS]
    event_name    
    ON SCHEDULE schedule
    [ON COMPLETION [NOT] PRESERVE]
    [ENABLE | DISABLE | DISABLE ON SLAVE]
    [COMMENT 'comment']
    DO sql_statement;

schedule:
    AT timestamp [+ INTERVAL interval] ...
  | EVERY interval 
    [STARTS timestamp [+ INTERVAL interval] ...] 
    [ENDS timestamp [+ INTERVAL interval] ...]

interval:
    quantity {YEAR | QUARTER | MONTH | DAY | HOUR | MINUTE |
              WEEK | SECOND | YEAR_MONTH | DAY_HOUR | DAY_MINUTE |
              DAY_SECOND | HOUR_MINUTE | HOUR_SECOND | MINUTE_SECOND}

Description:

This statement creates and schedules a new event. It requires the EVENT privilege for the schema in which the event is to be created.

The minimum requirements for a valid CREATE EVENT statement are as follows:

  • The keywords CREATE EVENT plus an event name, which uniquely identifies the event in the current schema. (Prior to MySQL 5.1.12, the event name needed to be unique only among events created by the same user on a given database.)
  • An ON SCHEDULE clause, which determines when and how often the event executes.
  • A DO clause, which contains the SQL statement to be executed by an event.

This is an example of a minimal CREATE EVENT statement:

CREATE EVENT myevent
    ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 1 HOUR
    DO
      UPDATE myschema.mytable SET mycol = mycol + 1;

The previous statement creates an event named myevent. This event executes once --- one hour following its creation --- by running an SQL statement that increments the value of the myschema.mytable table's mycol column by 1.

The event_name must be a valid MySQL identifier with a maximum length of 64 characters. It may be delimited using back ticks, and may be qualified with the name of a database schema. An event is associated with both a MySQL user (the definer) and a schema, and its name must be unique among names of events within that schema. In general, the rules governing event names are the same as those for names of stored routines. See http://dev.mysql.com/doc/refman/5.1/en/identifiers.html.

If no schema is indicated as part of event_name, the default (current) schema is assumed.

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