sql查詢是否打開狀態：SHOW VARIABLES LIKE 'event_scheduler'
用腳本來打開：
mysql -u root -p
mysql event_scheduler
開啓event_scheduler sql指令：
SET GLOBAL event_scheduler = ON;
SET @@global.event_scheduler = ON;
SET GLOBAL event_scheduler = 1;
SET @@global.event_scheduler = 1;
相反，關閉event_scheduler指令：
SET GLOBAL event_scheduler = OFF;
SET @@global.event_scheduler = OFF;
SET GLOBAL event_scheduler = 0;
SET @@global.event_scheduler = 0;