iteye_3754的博客

SHOW VARIABLES WHERE Variable_name = 'event_scheduler'; #开启mysql事件调度器功能 SET GLOBAL event_scheduler =1;  

SELECT * FROM a LEFT JOIN b ON a.aID = b.bID; a为主，a的数据全显示，连不上b的对应字段为空 SELECT * FROM a RIGHT JOIN b ON a.aID = b.bID; b为主，b的数据全显示，连不上a的对应字段为空 SELECT * FROM a INNER JOIN a ON a.aID = b.bID; 相...