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MySQL的计划任务创建

时间:2021-07-01 10:21:17 帮助过:26人阅读

实际项目中只想将最近7天的记录保存在MySQL数据库中,使用程序通过SQL指令的方式删除比较麻烦且效率低,用Mysql 提供的事件调度器

实际项目中只想将最近7天的记录保存在MySQL数据库中,使用程序通过SQL指令的方式删除比较麻烦且效率低,,用Mysql 提供的事件调度器(event scheduler)可轻松实现。

具体步骤如下:

1:超级用户方式登陆MySQL console

# mysql -uroot


2:打开event_scheduler(默认是关掉的)

mysql> set global event_scheduler = ON;

3:创建我们的事件(本例中命名为delete_old_record)

mysql> CREATE EVENT delete_old_record
   ON SCHEDULE EVERY 1 DAY STARTS NOW()
   DO
    -- delete the old records of demo_1_table
    DELETE FROM demo_1_table WHERE datediff(NOW(),log_timestamp)>=7;
    -- delete the old records of puma_2_table
    DELETE FROM demo_2_table WHERE datediff(NOW(),log_timestamp)>=7;
    -- delete the old records of puma_3_table
    DELETE FROM demo_3_table WHERE datediff(NOW(),log_timestamp)>=7;
    -- delete the old records of puma_4_table
    DELETE FROM demo_4_table WHERE datediff(NOW(),log_timestamp)>=7;

4:启动创建的事件

mysql> ALTER EVENT delete_old_record ENABLE;

这样以后,数据库就会每天执行DO后面的作业,删除各个table中7天之前的记录。

附录:CREATE EVENT的格式如下:

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 event_body;

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}

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