//mysql 根據時間相減,對24小時(即86400秒)之前的資料進行更新
update test set num=2 where TIME_TO_SEC(TIMEDIFF(now(),createTime))>86400




//建立儲存過程
CREATE PROCEDURE update_test() 
UPDATE test set num=num+1 where TIME_TO_SEC(TIMEDIFF(now(),createTime))>604800




//設定定時任務呼叫儲存過程
CREATE EVENT update_event
ON SCHEDULE EVERY 2 SECOND STARTS NOW() ON COMPLETION PRESERVE DO 
CALL update_test()