MySQL将select与来自其他表的sum结合起来(MySQL combine select with sum from other table)

MySQL将select与来自其他表的sum结合起来(MySQL combine select with sum from other table)

我对MySQL并不是很了解，但我需要一个声明，我真的很感谢你的帮助。

我有两张桌子：'用户'和'得分'

这是'用户'的结构：

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

这里是'得分'的结构：

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

现在我需要一个查询，为我提供某种高分列表。 结果应包含user_id，user_name以及与用户相关的所有分数的总和：我应该如下所示：

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

更好的是，如果结果将按照用户在全球排名中的位置排序，如下所示：

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

我试过这个声明

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_id从'user'连接到每行的'score'中的score_user_id。

非常感谢您的帮助

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

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

here's the structure of 'user':

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

here's the structure of 'score':

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

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 |

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 |

I tried the statement

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

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.

thank you very much for your help

最满意答案

您只需要按用户对您的分数进行分组：

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上看到它。 
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
 
See it on sqlfiddle.