+---------+----------------+--------+---------------------+---------------------+
| dev_idx | dev_ip_addr    | rtime  | ptime               | MAX(times.ptime)    |
+---------+----------------+--------+---------------------+---------------------+
|      40 | 192.168.52.252 | 10.001 | 0000-00-00 00:00:00 | 2007-01-17 08:58:07 |
|     221 | 192.168.24.43  |   NULL | NULL                | NULL                |
|     222 | 192.168.24.2   |   NULL | NULL                | NULL                |
|     223 | 192.168.24.3   |   NULL | NULL                | NULL                |
|     224 | 192.168.24.4   |   NULL | NULL                | NULL                |
|     225 | 192.168.24.5   |   NULL | NULL                | NULL                |
|     227 | 192.168.24.8   |   NULL | NULL                | NULL                |
|     228 | 192.168.24.15  |   NULL | NULL                | NULL                |
|     615 | 192.168.24.60  |  5.245 | 2007-01-17 09:30:54 | 2007-01-17 09:34:12 |
|     708 | 192.168.24.61  |   NULL | NULL                | NULL                |
|     709 | 192.168.24.62  |   NULL | NULL                | NULL                |
+---------+----------------+--------+---------------------+---------------------+