php - MySql 查询显示错误

Question

我的查询显示错误“on 子句”中的未知列“u.id”

我的查询

SELECT u.id,u.username ,sum(s.score) AS User_Score 
FROM
 `user` AS u ,
 `team_member` as tm
  LEFT JOIN score s ON (s.user_id=u.id and s.game_id=49 and s.team_id=27)
where tm.user_id=u.id and tm.team_id=27

Answer 1

您的加入不正确:

SELECT u.id,u.username ,sum(s.score) AS User_Score 
FROM
 `user` AS u join  `team_member` as tm on tm.user_id=u.id

  LEFT JOIN score s ON (s.user_id=u.id and s.game_id=49 and s.team_id=27)
where  tm.team_id=27
group by u.id,u.username 

如果使用join，则必须对所有表使用它，并且不能与where语句混合使用。