您好，这个语句：sql ORDER BY 的使用？如下所示！

Question

图片中 怎么样查出按posts_id分类，在同类中按reply_date降序排列。总的按send_time降序排列。各位大虾指点指点。

Answer 1

你都分类了。只能求同类中的reply_date了
SELECT a.posts_id,a.reply_date,a.send_time
FROM
TABLE A,
(
SELECT posts_id,MAX(reply_date) as reply_date
FROM TABLE
GROUP BY posts_id
) B
ON A.posts_id=B.posts_id AND A.reply_date=B.reply_date
ORDER BY B.send_time DESC

Answer 2

group by posts_id
order by reply_date desc,send_time desc
应该可以了