《MYSQL教程MySQL計(jì)劃任務(wù)(事件調(diào)度器) Event Scheduler介紹》要點(diǎn)：
本文介紹了MYSQL教程MySQL計(jì)劃任務(wù)(事件調(diào)度器) Event Scheduler介紹，希望對(duì)您有用。如果有疑問，可以聯(lián)系我們。

要查看當(dāng)前是否已開啟事件調(diào)度器,可執(zhí)行如下SQL：MYSQL入門

SHOW VARIABLES LIKE 'event_scheduler';
或MYSQL入門

SELECT @@event_scheduler;
或MYSQL入門

SHOW PROCESSLIST;
若顯示：MYSQL入門

+-----------------+-------+
| Variable_name?? | Value |
+-----------------+-------+
| event_scheduler | OFF?? |
+-----------------+-------+
則可執(zhí)行MYSQL入門

SET GLOBAL event_scheduler = 1;
或MYSQL入門

SET GLOBAL event_scheduler = ON;
來開啟,也可以直接在啟動(dòng)命令加上“Cevent_scheduler=1”,例如：MYSQL入門

mysqld ... --event_scheduler=1MYSQL入門

my.ini or my.cnf 中的
[mysqld]
添加 event_scheduler=ONMYSQL入門

創(chuàng)建事件(CREATE EVENT)
先來看一下它的語法：MYSQL入門

CREATE EVENT [IF NOT EXISTS] event_name
ON SCHEDULE schedule
[ON COMPLETION [NOT] PRESERVE]
[ENABLE | DISABLE]
[COMMENT 'comment']
DO sql_statement;MYSQL入門

schedule:
AT TIMESTAMP [+ INTERVAL INTERVAL]
| EVERY INTERVAL [STARTS TIMESTAMP] [ENDS TIMESTAMP]MYSQL入門

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入門

1)首先來看一個(gè)簡(jiǎn)單的例子來演示每秒插入一條記錄到數(shù)據(jù)表MYSQL入門

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秒鐘后,再執(zhí)行查詢成功.

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點(diǎn)整清空test表：MYSQL入門

CREATE EVENT e_test
ON SCHEDULE AT TIMESTAMP '2007-07-20 12:00:00'
DO TRUNCATE TABLE test.aaa;

4) 每天定時(shí)清空test表：MYSQL入門

CREATE EVENT e_test
ON SCHEDULE EVERY 1 DAY
DO TRUNCATE TABLE test.aaa;

5) 5天后開啟每天定時(shí)清空test表：MYSQL入門

CREATE EVENT e_test
ON SCHEDULE EVERY 1 DAY
STARTS CURRENT_TIMESTAMP + INTERVAL 5 DAY
DO TRUNCATE TABLE test.aaa;

6) 每天定時(shí)清空test表,5天后停止執(zhí)行：MYSQL入門

CREATE EVENT e_test
ON SCHEDULE EVERY 1 DAY
ENDS CURRENT_TIMESTAMP + INTERVAL 5 DAY
DO TRUNCATE TABLE test.aaa;

7) 5天后開啟每天定時(shí)清空test表,一個(gè)月后停止執(zhí)行：MYSQL入門

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]可以設(shè)置這個(gè)事件是執(zhí)行一次還是持久執(zhí)行,默認(rèn)為NOT PRESERVE.

8) 每天定時(shí)清空test表(只執(zhí)行一次,任務(wù)完成后就終止該事件)：MYSQL入門

CREATE EVENT e_test
ON SCHEDULE EVERY 1 DAY
ON COMPLETION NOT PRESERVE
DO TRUNCATE TABLE test.aaa;
[ENABLE | DISABLE]可是設(shè)置該事件創(chuàng)建后狀態(tài)是否開啟或關(guān)閉,默認(rèn)為ENABLE.
[COMMENT ‘comment']可以給該事件加上注釋.MYSQL入門

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) 臨時(shí)關(guān)閉事件MYSQL入門

ALTER EVENT e_test DISABLE;

2) 開啟事件MYSQL入門

ALTER EVENT e_test ENABLE;
3) 將每天清空test表改為5天清空一次：MYSQL入門

ALTER EVENT e_test
ON SCHEDULE EVERY 5 DAY;MYSQL入門

刪除事件(DROP EVENT)
語法很簡(jiǎn)單,如下所示：MYSQL入門

DROP EVENT [IF EXISTS] event_name
例如刪除前面創(chuàng)建的e_test事件MYSQL入門

DROP EVENT e_test;
當(dāng)然前提是這個(gè)事件存在,否則會(huì)產(chǎn)生ERROR 1513 (HY000): Unknown event錯(cuò)誤,因此最好加上IF EXISTSMYSQL入門

DROP EVENT IF EXISTS e_test;MYSQL入門

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