在MySQL中，如何找到在特定列上分组的N个最大值的总和? [英] In MySQL, how can I find the sum of the N largest values grouped on a particular column?

问题描述

可能重复:
mysql:在GROUP BY中使用LIMIT每组获得N个结果?

Possible Duplicate:
mysql: Using LIMIT within GROUP BY to get N results per group?

我有以下数据.

id      val
smith   20
smith   10
smith    8
smith   30
jones   40
jones   10
jones   30
jones   30

然后我想要的是按ID分组，然后将每个ID的两个最大值相加.

What I want then is to group by id and sum the two largest values for each id.

smith   50  from 30+20
jones   70  from 40+30

谢谢.

推荐答案

如果您不担心只获取每个ID的前两个值之和，则可以这样做:

If you weren't worried about getting the sum of only the top two values for each ID, you would want this:

SELECT SUM(val) FROM table_name GROUP BY id ORDER BY id ASC

但是，如何获取组中的前N个值"问题是重复的，请在此处回答:

However, the "How do I get the top N values within a group" question is a duplicate, answered here: Using LIMIT within GROUP BY to get N results per group?

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