MYSQL更新语句以按每个ID进行回填排名 [英] MYSQL update statement to backfill ranking by each id

问题描述

我正在尝试实现一个查询，即针对每个用户ID对得分进行排名并回填排名字段，以便

I was trying to implement a query, that for each userid, rank the score and backfill the rank field, so that

id | score | rank
1  |  100  | 0
1  |  200  | 0 
1  |  300  | 0
2  |  100  | 0
2  |  200  | 0
3  |  200  | 0

将成为

id | score | rank
1  |  100  | 3
1  |  200  | 2 
1  |  300  | 1
2  |  100  | 2
2  |  200  | 1
3  |  200  | 1

我在这里看到了类似的问题 用于存储排名位置的MySQL更新语句

I saw a similar question here MySQL update statement to store ranking positions

但是，就我而言，如何为每个ID进行"ID分组"?

However, in my case, how can I do the 'group by id' for each id?

推荐答案

这可能不是最漂亮的方法，但是您可以轻松地执行以下操作:

It might not be the prettiest way, but you can easily do something like:

set @rank = 0;
set @prev = 0;

select id, score, IF (id = @prev, @rank := @rank + 1, @rank := 1), @prev := id
from scores
order by id, score;

我想您也想要update语句，那就是:

I guess you want the update statement as well, and that would be:

set @rank = 0;
set @prev = 0;

update scores
set rank = IF(id = @prev, @rank := @rank + 1, @rank := 1),
id = (@prev := id)
order by id, score;

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