MySQL排名与关系 [英] MySQL Rank with ties

问题描述

我是新的sql，我从来没有使用变量或条件在mysql，但知道从其他编程语言。自从几天后，我试图找到一种方式来排名用户分数。我读了很多文章，还有问题，stackoverflow，最后我发现一个解决方案，几乎是它喜欢我想要的。

I am new to sql and I have never used variables or conditions in mysql, but know that from other programming languages. Since a few days I try to find a way to rank a user score. I read a lot of articles, and also questions that asked on stackoverflow and finally I found a solution that nearly does it like I want it.

SELECT
  score_users.uid,
  score_users.score,
  @prev := @curr,
  @curr := score,
  @rank := IF(@prev = @curr, @rank, @rank +1) AS rank
FROM
  score_users,
  (SELECT @curr := null, @prev := null, @rank := 0) tmp_tbl
WHERE
  score_users.matchday = 1
ORDER BY
  score_users.score DESC

但我的问题是打分。我不想得到连续的等级，例如：

But my Problems are tie scores. I don't want to get consecutive ranks, like this:

+------------+------+--------+
| uid | name  | rank | score |
+------------+------+--------+
| 4   | Jon   |   1  |  20   |
| 1   | Jane  |   2  |  19   |
| 2   | Fred  |   2  |  19   |
| 9   | July  |   3  |  18   |
| 7   | Mary  |   4  |  17   |
| 3   | Toni  |   5  |  12   |
| 5   | Steve |   5  |  12   |
| 6   | Peter |   6  |  11   |
| 8   | Nina  |   7  |  10   |
+------------+------+--------+

我想得到这样的结果：

+------------+------+--------+
| uid | name  | rank | score |
+------------+------+--------+
| 4   | Jon   |   1  |  20   |
| 1   | Jane  |   2  |  19   |
| 2   | Fred  |   2  |  19   |
| 9   | July  |   4  |  18   |
| 7   | Mary  |   5  |  17   |
| 3   | Toni  |   6  |  12   |
| 5   | Steve |   6  |  12   |
| 6   | Peter |   8  |  11   |
| 8   | Nina  |   9  |  10   |
+------------+------+--------+

我想我必须创建一个新的临时表，一些如果条件，但我找不到一个解决方案，变得绝望！
此外，我必须关注表现，也许有更好的方式来获得排名在得分，因为我做到了吗？我将非常感谢提示或一些代码片段。

I guess I have to create a new temporary table, and some if conditions, but I couldn't find a solution and become desperate! Also, I have to keep an eye on performance, maybe there are better ways to get the rank on score as I did it? I would be very grateful for hints or some code snippet.

推荐答案

您可以使用另一个变量来计数相同的排名，将 @rank 乘以1，将计数器值增加 @rank ，如下所示：

You can use another variable to count the same ranks so instead of incrementing @rank by 1, you increment @rank by the counter value, like this:

SELECT
  score_users.uid,
  score_users.score,
  @prev := @curr,
  @curr := score,
  @rank := IF(@prev = @curr, @rank, @rank + @i) AS rank,
  IF(@prev <> score, @i:=1, @i:=@i+1) AS counter
FROM
  score_users,
  (SELECT @curr := null, @prev := null, @rank := 0, @i := 0) tmp_tbl
WHERE
  score_users.matchday = 1
ORDER BY
  score_users.score DESC

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