Msyql Field函數講解【轉載】

此函數比較簡單，你們看看做爲了解便可：

 

MySQL能夠經過field()函數自定義排序，格式：field(value,str1,str2,str3,str4)，value與str一、str二、str三、str4比較，返回一、二、三、4，如遇到null或者不在列表中的數據則返回0. 這個函數好像Oracle中沒有專門提供（也多是我沒有用到），不過本身實現這樣一個函數仍是比較簡單的。

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)

 

轉載於：http://blog.csdn.net/lxz3000/article/details/6173873

參考資料：https://segmentfault.com/a/1190000003742537