MySQL自定义排序函数FIELD()

转载自:https://blog.csdn.net/lxz3000/article/details/6173873

MySQL可以通过field()函数自定义排序

格式:
field(value,str1,str2,str3,str4)

value与str1、str2、str3、str4比较,返回1、2、3、4,如遇到null或者不在列表中的数据则返回0. 这个函数好像Oracle中没有专门提供(也可能是我没有用到),不过自己实现这样一个函数还是比较简单的。

mysql> select * from driver_log order by name;

+--------+-------+------------+-------+
| rec_id | name  | trav_date  | miles |
+--------+-------+------------+-------+
|      1 | Ben   | 2006-08-30 |   152 |
|      9 | Ben   | 2006-09-02 |    79 |
|      5 | Ben   | 2006-08-29 |   131 |
|      8 | Henry | 2006-09-01 |   197 |
|      6 | Henry | 2006-08-26 |   115 |
|      4 | Henry | 2006-08-27 |    96 |
|      3 | Henry | 2006-08-29 |   300 |
|     10 | Henry | 2006-08-30 |   203 |
|      7 | Suzi  | 2006-09-02 |   502 |
|      2 | Suzi  | 2006-08-29 |   391 |
+--------+-------+------------+-------+

10 rows in set (0.00 sec)
mysql> select * from driver_log order by field(name,'Suzi','Ben','Henry');

+--------+-------+------------+-------+
| rec_id | name  | trav_date  | miles |
+--------+-------+------------+-------+
|      2 | Suzi  | 2006-08-29 |   391 |
|      7 | Suzi  | 2006-09-02 |   502 |
|      1 | Ben   | 2006-08-30 |   152 |
|      9 | Ben   | 2006-09-02 |    79 |
|      5 | Ben   | 2006-08-29 |   131 |
|      8 | Henry | 2006-09-01 |   197 |
|      6 | Henry | 2006-08-26 |   115 |
|      4 | Henry | 2006-08-27 |    96 |
|      3 | Henry | 2006-08-29 |   300 |
|     10 | Henry | 2006-08-30 |   203 |
+--------+-------+------------+-------+

10 rows in set (0.00 sec)

mysql> select * from driver_log order by field(name,'Suzi','Ben');

+--------+-------+------------+-------+
| rec_id | name  | trav_date  | miles |
+--------+-------+------------+-------+
|     10 | Henry | 2006-08-30 |   203 |
|      8 | Henry | 2006-09-01 |   197 |
|      6 | Henry | 2006-08-26 |   115 |
|      4 | Henry | 2006-08-27 |    96 |
|      3 | Henry | 2006-08-29 |   300 |
|      7 | Suzi  | 2006-09-02 |   502 |
|      2 | Suzi  | 2006-08-29 |   391 |
|      5 | Ben   | 2006-08-29 |   131 |
|      9 | Ben   | 2006-09-02 |    79 |
|      1 | Ben   | 2006-08-30 |   152 |
+--------+-------+------------+-------+

10 rows in set (0.00 sec)
mysql> select * from driver_log order by field(name,'Suzi','Ben') desc;

+--------+-------+------------+-------+
| rec_id | name  | trav_date  | miles |
+--------+-------+------------+-------+
|      1 | Ben   | 2006-08-30 |   152 |
|      9 | Ben   | 2006-09-02 |    79 |
|      5 | Ben   | 2006-08-29 |   131 |
|      2 | Suzi  | 2006-08-29 |   391 |
|      7 | Suzi  | 2006-09-02 |   502 |
|      8 | Henry | 2006-09-01 |   197 |
|      6 | Henry | 2006-08-26 |   115 |
|      4 | Henry | 2006-08-27 |    96 |
|      3 | Henry | 2006-08-29 |   300 |
|     10 | Henry | 2006-08-30 |   203 |
+--------+-------+------------+-------+

10 rows in set (0.00 sec)

猜你喜欢

转载自blog.csdn.net/u013991521/article/details/80873256