Mysql三表关联

发布网友发布时间：2022-05-07 16:21

共4个回答

懂视网时间：2022-05-07 20:42

bitsCN.com

mysql三表关联分组带where

mysql

查不出来：

SELECT e.id,e.ename,COUNT(s.id) AS total FROM enterprise e LEFT JOIN comm_port p ON e.id = p.eid LEFT JOIN sendedoutbox s ON p.port = s.CommPort WHERE s.SendTime BETWEEN '2013-08-09 15:31:35' AND '2013-08-28 10:47:28' GROUP BY p.eid ORDER BY total DESC

正确能查出来：

SELECT e.id,e.ename,COUNT(s.id) AS total FROM enterprise e LEFT JOIN comm_port p ON e.id = p.eid LEFT JOIN (SELECT * FROM sendedoutbox s WHERE s.SendTime BETWEEN '2013-08-09 15:31:35' AND '2013-08-28 10:47:28') s ON p.port = s.CommPort GROUP BY p.eid ORDER BY total DESC

bitsCN.com

热心网友时间：2022-05-07 17:50

ZHFLVG|五级

select * from table1 a,table2 b,table3 c
where a.设备1id=b.设备1id and a.设备2id=c.设备2id

项目经理说这样写sql发现全部改追问那应该怎么写呢？

热心网友时间：2022-05-07 19:08

select * from table1 a,table2 b,table3 c where a.1ID = b.1ID inner join a.1ID = C.2ID;追问PK FK用设置吗？怎么设置捏？

追答应该这样就行了

热心网友时间：2022-05-07 20:43

select * from table1 a,table2 b,table3 c
where a.设备1id=b.设备1id and a.设备2id=c.设备2id