MySQL 的一列与另一最大列不同

发布于 2024-12-09 19:56:31 字数 483 浏览 0 评论 0原文

假设我有这个查询：

SELECT report_id, time_sent
FROM  report_submissions
WHERE report_id IN (1,2,3,4,5,6)
ORDER BY report_id ASC, time_sent DESC

结果如下：

report_id   time_sent
1           2
1           1
2           4
2           3
3           4

我想更改该查询，以便我将获得一个 DISTINCT report_id 及其 max(time_sent)，例如：

report_id   time_sent
1           2
2           4
3           4

如何以最有效的方式做到这一点？谢谢。

原文

Let's say I have this query:

SELECT report_id, time_sent
FROM  report_submissions
WHERE report_id IN (1,2,3,4,5,6)
ORDER BY report_id ASC, time_sent DESC

with this result:

report_id   time_sent
1           2
1           1
2           4
2           3
3           4

And I want to change that query so I will get a DISTINCT report_id with its max(time_sent), for example:

report_id   time_sent
1           2
2           4
3           4

How do I do that in the most efficient way? Thanks.

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原野 2024-12-16 19:56:31

SELECT report_id, max(time_sent)
FROM  report_submissions
WHERE report_id IN (1,2,3,4,5,6)
GROUP BY report_id
ORDER BY report_id ASC

SELECT report_id, max(time_sent)
FROM  report_submissions
WHERE report_id IN (1,2,3,4,5,6)
GROUP BY report_id
ORDER BY report_id ASC

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坏尐絯℡ 2024-12-16 19:56:31

DISTINCT 是一个懒惰的GROUP BY！

SELECT report_id, max(time_sent)
FROM  report_submissions
WHERE report_id IN (1,2,3,4,5,6)
GROUP BY report_id
ORDER BY report_id ASC, max(time_sent) DESC

DISTINCT is a lazy GROUP BY!

SELECT report_id, max(time_sent)
FROM  report_submissions
WHERE report_id IN (1,2,3,4,5,6)
GROUP BY report_id
ORDER BY report_id ASC, max(time_sent) DESC

回复收藏 0 原文