關於MySQL多表連線查詢
阿新 • • 發佈:2021-02-07
select a.*,c.device_name from device_warn as a inner join user_warn as b on a.id=b.warn_id and b.state=1 inner join device_info as c on c.DEVICE_ID=a.DEVICE_ID where a.DEVICE_ID in (select DEVICE_ID from device_station where STATION_ID in (select STATION_ID from station_user where USER_ID=4))
本條sql語句涉及到了三個表的聯查,分別是device_warn,user_warn,device_info,
其中,device_warn,user_warn,device_info的表結構分別如下:
易錯問題,where條件必須在join條件之後。