要查看當前是否已開啟事件調(diào)度器,可執(zhí)行如下SQL:
SHOW VARIABLES LIKE 'event_scheduler';
或
SELECT @@event_scheduler;
或
SHOW PROCESSLIST;
若顯示:
+-----------------+-------+
| Variable_name | Value |
+-----------------+-------+
| event_scheduler | OFF |
+-----------------+-------+
則可執(zhí)行
SET GLOBAL event_scheduler = 1;
或
SET GLOBAL event_scheduler = ON;
來開啟,也可以直接在啟動命令加上“–event_scheduler=1”,例如:
mysqld ... --event_scheduler=1
my.ini or my.cnf 中的
[mysqld]
添加 event_scheduler=ON
創(chuàng)建事件(CREATE EVENT)
先來看一下它的語法:
CREATE EVENT [IF NOT EXISTS] event_name
ON SCHEDULE schedule
[ON COMPLETION [NOT] PRESERVE]
[ENABLE | DISABLE]
[COMMENT 'comment']
DO sql_statement;
schedule:
AT TIMESTAMP [+ INTERVAL INTERVAL]
| EVERY INTERVAL [STARTS TIMESTAMP] [ENDS TIMESTAMP]
INTERVAL:
quantity {YEAR | QUARTER | MONTH | DAY | HOUR | MINUTE |
WEEK | SECOND | YEAR_MONTH | DAY_HOUR | DAY_MINUTE |
DAY_SECOND | HOUR_MINUTE | HOUR_SECOND | MINUTE_SECOND}
1)首先來看一個簡單的例子來演示每秒插入一條記錄到數(shù)據(jù)表
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點整清空test表:
CREATE EVENT e_test
ON SCHEDULE AT TIMESTAMP '2007-07-20 12:00:00'
DO TRUNCATE TABLE test.aaa;
4) 每天定時清空test表:
CREATE EVENT e_test
ON SCHEDULE EVERY 1 DAY
DO TRUNCATE TABLE test.aaa;
5) 5天后開啟每天定時清空test表:
CREATE EVENT e_test
ON SCHEDULE EVERY 1 DAY
STARTS CURRENT_TIMESTAMP + INTERVAL 5 DAY
DO TRUNCATE TABLE test.aaa;
6) 每天定時清空test表,5天后停止執(zhí)行:
CREATE EVENT e_test
ON SCHEDULE EVERY 1 DAY
ENDS CURRENT_TIMESTAMP + INTERVAL 5 DAY
DO TRUNCATE TABLE test.aaa;
7) 5天后開啟每天定時清空test表,一個月后停止執(zhí)行:
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)置這個事件是執(zhí)行一次還是持久執(zhí)行,默認為NOT PRESERVE。
8) 每天定時清空test表(只執(zhí)行一次,任務(wù)完成后就終止該事件):
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,默認為ENABLE。
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