MySQL链内JOIN错误

Question

当我登录一个用户时，我想检索他的个人信息，例如他的类(class)和团队。我设法检索类(class)，但是当我尝试检索团队时，它不起作用。

我有 3 个表(用户、团队和类(class))和 2 个联接表(teams_users 和classes_users)。

关系如下:

classes (id_classe) <--> classes_users (classe_id, user_id ) <--> users (id_user)

teams (id_team) <--> teams_users (team_id, user_id) <--> users (id_user)

这有效

SELECT * FROM classes `c` 
INNER JOIN (SELECT * FROM classes_users `cu` 
INNER JOIN (SELECT * FROM users WHERE (users.email = 'tata@gmail.com'))
`u` ON (u.id_user = cu.user_id)) 
`ui` ON (ui.classe_id = c.id_classe)

但是当我尝试在下面添加另一个联接时，它不起作用。

SELECT * FROM teams_users `tu` 
INNER JOIN (SELECT * FROM classes `c` 
INNER JOIN (SELECT * FROM classes_users `cu` 
INNER JOIN (SELECT * FROM users WHERE (users.email = 'tata@gmail.com')) 
`u` ON (u.id_user = cu.user_id))
`ui`ON (ui.classe_id = c.id_classe)) 
`wc` ON (wc.id_user = tu.user_id)

Answer 1

为什么有所有括号和子查询？我认为这就是您正在尝试做的事情:

SELECT *
FROM teams_users tu INNER JOIN 
     users u
     ON u.id_user = tu.user_id INNER JOIN
     class_users cu
     ON u.id_user = cu.user_id INNER JOIN
     classes c
     ON cu.classe_id = c.id_classe
WHERE u.email = 'tata@gmail.com';