Question

假设表

team: id, title
team_user: id_team, id_user

我想选择只有指定成员的团队。在这个例子中，我想要团队，其中唯一的用户是id为1和5的用户，没有其他用户。我提出了这个SQL，但对于这么简单的任务来说似乎有点过分。

SELECT team.*, COUNT(`team_user`.id_user) AS cnt
FROM `team`
JOIN `team_user` user0 ON `user0`.id_team = `team`.id AND `user0`.id_user = 1
JOIN `team_user` user1 ON `user1`.id_team = `team`.id AND `user1`.id_user = 5
JOIN `team_user` ON `team_user`.id_team = `team`.id
GROUP BY `team`.id
HAVING cnt = 2

编辑：谢谢大家的帮助。如果您想真正尝试您的想法，可以使用示例数据库结构和数据：http://down.lipe.cz/team_members.sql

Answer 1

怎么样

SELECT *
FROM team t
JOIN team_user tu ON (tu.id_team = t.id)
GROUP BY t.id
HAVING (SUM(tu.id_user IN (1,5)) = 2) AND (SUM(tu.id_user NOT IN (1,5)) = 0)

我在team_user（id_team，id_user）上假设一个唯一索引。

Answer 2

您可以使用

SELECT
    DISTINCT id,
    COUNT(tu.id_user) as cnt 
FROM
    team t 
    JOIN team_user tu ON ( tu.id_team = t.id )
GROUP BY  
     t.id
HAVING
    count(tu.user_id) = count( CASE WHEN tu.user_id = 1 or tu.user_id = 5 THEN 1 ELSE 0 END )
    AND cnt = 2

不确定为什么您需要cnt = 2条件，该查询只会获得所有用户ID 1 or 5

的所有用户

Answer 3

试试这个

SELECT team.*, COUNT(`team_user`.id_user) AS cnt FROM `team`
JOIN `team_user` ON `team_user`.id_team = `team`.id
where `team_user`.id_user IN (1,5)
GROUP BY `team`.id
HAVING cnt = 2

（我的）SQL JOIN - 获得具有确切指定成员的团队

3 个答案: