适用于mysql 5.5+，定时任务完整示例。
场景任务：要求每天凌晨执行以下语句：
update last_modify set time = now() where user_name = ‘jeeinn’;
一、查看mysql的event是否开启
show variables like ‘%sche%’;
设置event_scheduler为开启状态：
set global event_scheduler =1;
二、创建存储过程update_modify
CREATE PROCEDURE update_modify ()
BEGIN
update last_modify set time = now() where user_name = ‘jeeinn’;
END;
三、创建定时任务event do_update_modify
create event if not exists do_update_modify
on schedule every 1 day starts ‘2016-07-20 00:00:00’
on completion preserve
do call update_modify();
关闭事件任务
alter event do_update_modify ON COMPLETION PRESERVE DISABLE;
开启事件任务
alter event do_update_modify ON COMPLETION PRESERVE ENABLE;
删除事件任务
drop event if exists do_update_modify
修改事件任务
alter event do_update_modify [ON SCHEDULE schedule] [RENAME TO new_event_name]
[ON COMPLETION [NOT] PRESERVE] [COMMENT ‘comment’] [ENABLE | DISABLE] [DO
sql_statement]
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