php - 从每个 user_id 不同的表中选择所有列

Question

我正在创建一个活动提要，显示我的用户活动，该活动仅限于最后 5 行。

SELECT * FROM activity ORDER BY date desc LIMIT 5

问题是我不希望活动提要在任何时候都被同一个用户弄乱，所以我想检索 user_id 彼此不同的最后 5 个结果。

我怎么能这样做呢？

Answer 1

这应该有效：

SELECT user_id, MAX(date) FROM activity GROUP BY user_id ORDER BY date DESC LIMIT 5

Answer 2

如果每个用户都没有多个max(date)，则可以使用：

SELECT *
FROM   activity
WHERE  (user_id, `date`) IN (
  SELECT * FROM (
    SELECT   user_id, max(`date`)
    FROM     activity
    GROUP BY user_id
    ORDER BY max(`date`) DESC
    LIMIT 5) s
  )
ORDER BY `date` DESC

请在此处查看小提琴。

Answer 3

我想使用这样的查询会很容易

SELECT DISTINCT activity.user_id,activity.* order by date DESC limit 5

Mysql Distinct 参考：http ://dev.mysql.com/doc/refman/5.1/en/distinct-optimization.html

Answer 4

它可以帮助你。

SELECT * FROM activity GROUP BY user ORDER BY date DESC LIMIT 5

Answer 5

试试这个查询，SELECT DISTINCT * FROM activity ORDER BY date desc LIMIT 5