id | search_id | user_id | data | action | activitable_id | activitable_type | created_at | updated_at
-----+-----------+---------+----------+--------+----------------+------------------+----------------------------+----------------------------
213 | 1 | 2 | --- +| 1 | 69801 | Mention | 2014-09-25 23:28:55.592874 | 2014-09-25 23:28:55.592874
| | | taglist:+| | | | |
| | | - - 54 +| | | | |
| | | | | | | |
212 | 1 | 2 | --- +| 1 | 69803 | Mention | 2014-09-25 23:28:49.173146 | 2014-09-25 23:28:49.173146
| | | taglist:+| | | | |
| | | - - 73 +| | | | |
211 | 1 | 2 | --- +| 1 | 69802 | Mention | 2014-09-25 23:28:45.132325 | 2014-09-25 23:28:45.132325
| | | taglist:+| | | | |
| | | - - 73 +| | | | |
210 | 1 | 1 | --- +| 1 | 69801 | Mention | 2014-09-25 21:43:43.61208 | 2014-09-25 21:43:43.61208
| | | taglist:+| | | | |
| | | - - 73 +| | | | |
209 | 1 | 1 | --- +| 1 | 69833 | Mention | 2014-09-23 12:51:47.973599 | 2014-09-23 12:51:47.973599
| | | taglist:+| | | | |
| | | - - 54 +| | | | |
208 | 1 | 1 | --- +| 1 | 69836 | Mention | 2014-09-23 12:51:41.396198 | 2014-09-23 12:51:41.396198
| | | taglist:+| | | | |
| | | - - 54 +| | | | |
| | | | | | | |
207 | 1 | 1 | --- +| 1 | 69832 | Mention | 2014-09-23 12:51:36.552109 | 2014-09-23 12:51:36.552109
| | | taglist:+| | | | |
| | | - - 66 +| | | |
(7 rows)
我有这些user_activity表。我想用user_id和created_at日期对它进行分组，间隔为一天。我可以使用user_id和created_at对其进行分组（但没有一天的间隔）