MySQL事件调度器 CREATE EVENT

转载：http://blog.csdn.net/abandonship/article/details/7050285

MySQL从5.1开始支持Event功能，有点类似于MsSQL的Job，可以定时自动执行数据汇总。
【语法】

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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} 

其中，
event_name：定时器名，最大长度64个字符，若未指定，则默认为当前的MySQL用户名(不区分大小写)；
schedule：限定执行时间；
ON COMPLETION [NOT] PRESERVE：表示是否需要循环复用这个Event；
sql_statement：要执行的SQL语句（也可以使用存储过程代替传统的SQL语句）；
comment：对该时间调度器的一个注释，最大长度64个字符；

【关闭事件】

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ALTER EVENT event_name ON  
COMPLETION PRESERVE DISABLE;  

【开启事件】

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ALTER EVENT event_name ON  
COMPLETION PRESERVE ENABLE;  

【删除事件】

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DROP EVENT [IF EXISTS] event_name  

【注意】：要使用定时器，MySQL的常量GLOBAL event_scheduler必须为on或者是1.

【范例】
1. 每天凌晨1点开始执行数据更新:

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CREATE EVENT [IF NOT EXISTS] E_testEvent_1   
    ON SCHEDULE EVERY 1 DAY STARTS DATE_ADD(DATE_ADD(CURDATE(), INTERVAL 1 DAY), INTERVAL 1 HOUR)   
    ON COMPLETION PRESERVE ENABLE   
    DO  
        UPDATE _T_test SET col= 2 where ValidityDate < now(); 

2. 每月第一天凌晨1点开始执行数据更新(使用存储过程):

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CREATE EVENT E_testEvent_2   
    ON SCHEDULE EVERY 1 MONTH STARTS DATE_ADD(DATE_ADD(DATE_SUB(CURDATE(),INTERVAL DAY(CURDATE())-1 DAY), INTERVAL 1 MONTH),INTERVAL 1 HOUR)  
    ON COMPLETION PRESERVE ENABLE  
    DO  
    BEGIN  
        CALL P_testProcedureName();  

    END 
3. 每季度第一天凌晨1点开始执行数据更新：

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CREATE EVENT E_testEvent_3    
    ON SCHEDULE EVERY 1 QUARTER STARTS DATE_ADD(DATE_ADD(DATE( CONCAT(YEAR(CURDATE()),'-',ELT(QUARTER(CURDATE()),1,4,7,10),'-',1)),INTERVAL 1 QUARTER),INTERVAL 2 HOUR)  
    ON COMPLETION PRESERVE ENABLE  
    DO  
        UPDATE _T_test SET col= 2 where ValidityDate < now(); 

【一些Event相关语句】：
1. 查看是否开启定时器

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SHOW VARIABLES LIKE '%sche%';  

2. 开启定时器 0：off 1：on

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SET GLOBAL event_scheduler = 1;