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《MYSQL教程MySQL计划任务(事件调度器) Event Scheduler介绍》要点：
本文介绍了MYSQL教程MySQL计划任务(事件调度器) Event Scheduler介绍，希望对您有用。如果有疑问，可以联系我们。
要查看当前是否已开启事件调度器,可执行如下SQL：MYSQL入门
SHOW VARIABLES LIKE 'event_scheduler';
或MYSQL入门
SELECT @@event_scheduler;
或MYSQL入门
SHOW PROCESSLIST;
若显示：MYSQL入门
+-----------------+-------+
| Variable_name?? | Value |
+-----------------+-------+
| event_scheduler | OFF?? |
+-----------------+-------+
则可执行MYSQL入门
SET GLOBAL event_scheduler = 1;
或MYSQL入门
SET GLOBAL event_scheduler = ON;
来开启,也可以直接在启动命令加上“Cevent_scheduler=1”,例如：MYSQL入门
mysqld ... --event_scheduler=1MYSQL入门
my.ini or my.cnf 中的
[mysqld]
添加 event_scheduler=ONMYSQL入门
创建事件(CREATE EVENT)
先来看一下它的语法：MYSQL入门
CREATE EVENT [IF NOT EXISTS] event_name
ON SCHEDULE schedule
[ON COMPLETION [NOT] PRESERVE]
[ENABLE | DISABLE]
[COMMENT 'comment']
DO sql_statement;MYSQL入门
schedule:
AT TIMESTAMP [+ INTERVAL INTERVAL]
| EVERY INTERVAL [STARTS TIMESTAMP] [ENDS TIMESTAMP]MYSQL入门
INTERVAL:
quantity {YEAR | QUARTER | MONTH | DAY | HOUR | MINUTE |
??????????? WEEK | SECOND | YEAR_MONTH | DAY_HOUR | DAY_MINUTE |
??????????? DAY_SECOND | HOUR_MINUTE | HOUR_SECOND | MINUTE_SECOND}MYSQL入门
1)首先来看一个简单的例子来演示每秒插入一条记录到数据表MYSQL入门
USE test;
CREATE TABLE aaa (timeline TIMESTAMP);
CREATE EVENT e_test_insert
ON SCHEDULE EVERY 1 SECOND
DO INSERT INTO test.aaa VALUES (CURRENT_TIMESTAMP);
等待3秒钟后,再执行查询成功.
2) 5天后清空test表：
CREATE EVENT e_test
ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 5 DAY
DO TRUNCATE TABLE test.aaa;
3) 2007年7月20日12点整清空test表：MYSQL入门
CREATE EVENT e_test
ON SCHEDULE AT TIMESTAMP '2007-07-20 12:00:00'
DO TRUNCATE TABLE test.aaa;
4) 每天定时清空test表：MYSQL入门
CREATE EVENT e_test
ON SCHEDULE EVERY 1 DAY
DO TRUNCATE TABLE test.aaa;
5) 5天后开启每天定时清空test表：MYSQL入门
CREATE EVENT e_test
ON SCHEDULE EVERY 1 DAY
STARTS CURRENT_TIMESTAMP + INTERVAL 5 DAY
DO TRUNCATE TABLE test.aaa;
6) 每天定时清空test表,5天后停止执行：MYSQL入门
CREATE EVENT e_test
ON SCHEDULE EVERY 1 DAY
ENDS CURRENT_TIMESTAMP + INTERVAL 5 DAY
DO TRUNCATE TABLE test.aaa;
7) 5天后开启每天定时清空test表,一个月后停止执行：MYSQL入门
CREATE EVENT e_test
ON SCHEDULE EVERY 1 DAY
STARTS CURRENT_TIMESTAMP + INTERVAL 5 DAY
ENDS CURRENT_TIMESTAMP + INTERVAL 1 MONTH
DO TRUNCATE TABLE test.aaa;
[ON COMPLETION [NOT] PRESERVE]可以设置这个事件是执行一次还是持久执行,默认为NOT PRESERVE.
8) 每天定时清空test表(只执行一次,任务完成后就终止该事件)：MYSQL入门
CREATE EVENT e_test
ON SCHEDULE EVERY 1 DAY
ON COMPLETION NOT PRESERVE
DO TRUNCATE TABLE test.aaa;
[ENABLE | DISABLE]可是设置该事件创建后状态是否开启或关闭,默认为ENABLE.
[COMMENT ‘comment']可以给该事件加上注释.MYSQL入门
修改事件(ALTER EVENT)
ALTER EVENT event_name
[ON SCHEDULE schedule]
[RENAME TO new_event_name]
[ON COMPLETION [NOT] PRESERVE]
[COMMENT 'comment']
[ENABLE | DISABLE]
[DO sql_statement]
1) 临时关闭事件MYSQL入门
ALTER EVENT e_test DISABLE;
2) 开启事件MYSQL入门
ALTER EVENT e_test ENABLE;
3) 将每天清空test表改为5天清空一次：MYSQL入门
ALTER EVENT e_test
ON SCHEDULE EVERY 5 DAY;MYSQL入门
删除事件(DROP EVENT)
语法很简单,如下所示：MYSQL入门
DROP EVENT [IF EXISTS] event_name
例如删除前面创建的e_test事件MYSQL入门
DROP EVENT e_test;
当然前提是这个事件存在,否则会产生ERROR 1513 (HY000): Unknown event错误,因此最好加上IF EXISTSMYSQL入门
DROP EVENT IF EXISTS e_test;MYSQL入门 （编辑：李大同）
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