我必须显示下面的查询结果,按优先级排序。
mysql> select CouponId, CouponCode, DateAdded, Priority from Coupon where IsFeatured=1 and IsApproved=1 order by DateAdded desc limit 12;
+----------+--------------+---------------------+----------+
| CouponId | CouponCode | DateAdded | Priority |
+----------+--------------+---------------------+----------+
| 42699 | cc2 | 2013-09-12 14:54:39 | NULL |
| 42698 | c1 | 2013-09-12 14:53:36 | NULL |
| 42697 | cc2 | 2013-09-12 14:51:57 | NULL |
| 42679 | GLMR20 | 2013-05-14 13:21:07 | 5 |
| 42678 | HKBAJAJ20 | 2013-05-14 12:35:31 | 1 |
| 42677 | SIPPER51 | 2013-05-14 12:11:36 | NULL |
| 42654 | GL13MAYCHILL | 2013-05-14 07:09:08 | 7 |
| 41978 | POLARSPL | 2013-05-03 13:31:32 | NULL |
| 41958 | COMBO30 | 2013-05-03 12:16:53 | NULL |
| 41357 | BRANDED60 | 2013-04-25 13:49:56 | NULL |
| 41073 | PKCCR500 | 2013-04-22 11:10:27 | NULL |
| 40794 | SWC15 | 2013-04-18 13:57:54 | NULL |
+----------+--------------+---------------------+----------+
12 rows in set (0.00 sec)
我虽然 Priority desc 的另一个订单会这样做,但它会产生相同的结果
mysql> select CouponId, CouponCode, DateAdded, Priority from Coupon where IsFeatured=1 and IsApproved=1 order by DateAdded desc, Priority desc limit 12;
+----------+--------------+---------------------+----------+
| CouponId | CouponCode | DateAdded | Priority |
+----------+--------------+---------------------+----------+
| 42699 | cc2 | 2013-09-12 14:54:39 | NULL |
| 42698 | c1 | 2013-09-12 14:53:36 | NULL |
| 42697 | cc2 | 2013-09-12 14:51:57 | NULL |
| 42679 | GLMR20 | 2013-05-14 13:21:07 | 5 |
| 42678 | HKBAJAJ20 | 2013-05-14 12:35:31 | 1 |
| 42677 | SIPPER51 | 2013-05-14 12:11:36 | NULL |
| 42654 | GL13MAYCHILL | 2013-05-14 07:09:08 | 7 |
| 41978 | POLARSPL | 2013-05-03 13:31:32 | NULL |
| 41958 | COMBO30 | 2013-05-03 12:16:53 | NULL |
| 41357 | BRANDED60 | 2013-04-25 13:49:56 | NULL |
| 41073 | PKCCR500 | 2013-04-22 11:10:27 | NULL |
| 40794 | SWC15 | 2013-04-18 13:57:54 | NULL |
+----------+--------------+---------------------+----------+
12 rows in set (0.00 sec)
mysql>
如何按优先级排序此查询的结果。这样优先级为 7 的行就会出现在顶部,而不管其添加日期如何。我需要在查询中按 DateAdded 排序,只选择前 12 行 wrt time,然后根据 priority 对它们进行排序。这怎么可能 ?