MySQL的总和和组给予错误的结果

Question

我使用下面的表格......

stats (id, game, user_id, rank, score, dnt) 
teams(id, name, dnt) 
users(id, username, email, team_id, dnt) 

我要抢根据统计排名前10位的高得分的球队（球队总比分被其使用者对总成绩）

为统计样本数据...

| id | game | user_id | rank | score | dnt | 
+----+------+---------+-------+------+-----+ 
| 1 | test | 5  | 2 | 2200 | 
+--------+----------+----------+-----+-----+ 
| 2 | test | 3  | 1 | 2500 | 
+--------+----------+----------+-----+-----+ 

队

| id | name | dnt | 
+----+-------+-----+ 
| 1 | team1 |  | 
+----+-------+-----+ 
| 2 | team2 |  | 
+----+-------+-----+ 

个

用户

| id | username | email | team_id | 
+----+----------+-------+---------+ 
| 1 | user1 |  | 1  | 
+----+----------+-------+---------+ 
| 1 | user2 |  | 2  | 
+----+----------+-------+---------+ 

，我想下面的SQL查询...

SELECT t.name as team_name, sum(s.score) as total_score 
     FROM teams t 
     JOIN users u ON u.team_id = t.id 
     JOIN stats s ON s.user_id = u.id 
     GROUP BY team_name ORDER BY total_score DESC 

但上面的查询将返回0行，即使我想你帮忙写TP往上顶10用户得分。

感谢您的帮助。

Answer 1

您的user_id在stats表无处可在您的users表中找到。你甚至有2个用户使用相同的id？您的查询返回正确的结果。

SELECT t.name as team_name, sum(s.score) as total_score 
FROM teams t 
INNER JOIN users u 
    ON u.team_id = t.id 
INNER JOIN stats s 
    ON s.user_id = u.id 
GROUP BY team_name 
ORDER BY total_score DESC 
LIMIT 10