Msyql Field函数讲解【转载】

此函数比较简单，大家看看作为了解即可：

 

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)

 

转载于：http://blog.csdn.net/lxz3000/article/details/6173873

参考资料：https://segmentfault.com/a/1190000003742537