Question

+----+----------+-------------+-----------+---------------------+---------+---------------------------+
| id | action   | object_type | object_id | created_at          | user_id | object_title              |
+----+----------+-------------+-----------+---------------------+---------+---------------------------+
|  1 | shared   |           0 |         1 | 2016-04-22 06:13:16 |       1 | 5 highest buildings       |
|  2 | liked    |           0 |         1 | 2016-04-22 06:15:02 |       1 | 5 highest buildings       |
|  3 | liked    |           0 |         1 | 2016-05-21 19:02:18 |       2 | 5 highest buildings       |
|  4 | liked    |           1 |         3 | 2016-05-21 19:02:21 |       3 | 5 largest bridges         |
+----+----------+-------------+-----------+---------------------+---------+---------------------------+

我试图建立一些类似于Facebook新闻源的东西。我的意思是当我朋友列表中的多个用户喜欢同一个帖子时，我们只会在新闻Feed中显示单个结果，说明friend1，friend2，frnd3等，就像这个xyz帖子一样。

在此表格中，我想分组这三列（action，object_type，object_id）以及此对象的用户列表。

SELECT *
FROM mytable
GROUP BY action, object_type, object_id

但这给了我一些奇怪的结果，我期待着一个用户列表。我＆＃39;真的没有任何线索如何在这个查询中做到这一点。

任何帮助或领导都将不胜感激。

Answer 1

尝试此查询

SELECT action, object_title,count(user_id) as user_count, group_concat(user_id) as user_ids 
   FROM mytable GROUP BY action, object_type, object_id;

SQL列在多列上 - MySQL

1 个答案: