MySQL将select与其他表中的sum结合起来

MySQL combine select with sum from other table(MySQL将select与其他表中的sum结合起来)

问题描述

我不是很喜欢 MySQL，但我只需要一个声明，我非常感谢您在这方面的帮助.

i'm not really much into MySQL, but i need just one statement and I would really appreciate your help on this.

我有两个表:'user' 和 'score'

I have two tables: 'user' and 'score'

这是用户"的结构:

| user_id | user_name |
| 1       | Paul      |
| 2       | Peter     |

这是'score'的结构:

here's the structure of 'score':

| score_id | score_user_id | score_track_id | score_points | 
| 1        | 2             | 23             | 200          |
| 2        | 2             | 25             | 150          |

现在我需要一个能够为我提供某种高分列表的查询.结果应包含 user_id、user_name 和与用户相关的所有分数的总和:我应该如下所示:

now I need a query that provides me some kind of highscore-list. the result should contain user_id, user_name and the sum of all scores that are related to the user: i should look like this:

| user_id | user_name | scores |
| 1       | Paul      | 0      |
| 2       | Peter     | 350    |

如果将结果按照用户在全球排名中的位置排序，则更好:

even better would be, if the result would be sorted in order of the users position in the global ranking like this:

| position | user_id | user_name | scores |
| 1        | 2       | Peter     | 350    |
| 2        | 1       | Paul      | 0      |

我试过这个说法

SELECT user_id as current_user, user_name, SUM(SELECT score_points FROM score WHERE score_user_id = current_user) as ranking FROM user ORDER BY ranking DESC

这会导致语法错误.对我来说主要的问题是将'user'中的user_id连接到每行'score'中的score_user_id.

which results in a syntax error. the main problem for me is to connect the user_id from 'user' to the score_user_id in 'score' for each row.

非常感谢您的帮助

推荐答案

你只需要将你的分数按用户分组:

You just need to group your scores by user:

SELECT @p:=@p+1 AS position, t.*
FROM (
  SELECT   user.user_id,
           user.user_name,
           IFNULL(SUM(score.score_points),0) AS total_points
  FROM     user LEFT JOIN score ON user.user_id = score.score_user_id
  GROUP BY user.user_id
  ORDER BY total_points DESC
) AS t JOIN (SELECT @p:=0) AS initialisation

在 sqlfiddle 上查看它.

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