mysql定时任务

创建存储过程，保留100条数据，其他删除

DELIMITER |
DROP PROCEDURE IF EXISTS clear_bzp_dynamic_supervision_data |
CREATE PROCEDURE clear_bzp_dynamic_supervision_data()
    BEGIN  
      
       SET @count_=(SELECT COUNT(id) FROM bzp_dynamic_supervision);
       IF(@count_>100) THEN 
        
        SET @max_id=(SELECT MAX(id) FROM bzp_dynamic_supervision);
        SET @max_id = @max_id - 100;
            DELETE FROM `bzp_dynamic_supervision` WHERE id<@max_id;
            
       END IF ;
       
    END
|

创建定时任务：每晚四点触发

SET GLOBAL event_scheduler = 1; 
CREATE EVENT IF NOT EXISTS clear_bzp_dynamic_supervision_data
 
on schedule EVERY 1 DAY STARTS '2018-12-06 04:00:00'
ON COMPLETION PRESERVE  
 
DO CALL clear_bzp_dynamic_supervision_data();

启动定时任务：

ALTER EVENT clear_bzp_dynamic_supervision_data ON 
 
COMPLETION PRESERVE ENABLE;