+---------+---------------------+---------------------+
| area_id | date_1 | date_2 |
+---------+---------------------+---------------------+
| NULL | 2012-06-28 10:09:18 | 2012-06-28 10:15:48 |
| 18 | 2012-06-28 10:15:48 | 2012-06-28 10:20:26 |
| 21 | 2012-06-28 10:20:26 | 2012-06-28 10:32:51 |
| 3 | 2012-06-28 10:32:51 | 2012-06-28 10:50:27 |
| 21 | 2012-06-28 10:50:27 | 2012-06-28 11:36:36 |
| 18 | 2012-06-28 11:36:36 | 2012-06-28 11:39:26 |
| 21 | 2012-06-28 11:39:26 | 2012-06-28 11:40:33 |
| 3 | 2012-06-28 11:40:33 | 2012-06-28 11:48:03 |
| 7 | 2012-06-28 11:48:03 | NULL |
+---------+---------------------+---------------------+
请帮助我确定 area_id beetwen date1 和 date_2 的范围
datetime.now() - date_2
谢谢