[总结] mysql 先排序再分组

src: http://www.oschina.net/question/123890_35887

比如一个评论表:
id uid title content ctime

取出最近的 10 条评论, 一条人发的多条评论的只取一条

SELECT MAX(id) AS max_id
FROM table1
GROUP BY uid
ORDER BY max_id DESC