我想根据条件加入两个表.
表A:
+--------+-------------+------+
| prefix | Destination | rate |
+----------------------+------+
| 56 | Monn | 25 |
| 5602 | Monn M1 | 23 |
| 5604 | Monn M3 | 44 |
| 5607 | Monn M1 | 23 |
| 5625 | Monn M2 | 22 |
| 23 | Xpia | 0.3 |
| 238 | Xpia F3 | 0.9 |
+--------+-------------+------+
表B:
+--------+-------------+------+
| prefix | Destination | rate |
+----------------------+------+
| 56 | Monn …