field

SinceVersion dev

field

description

Syntax

field(Expr e, param1, param2, param3,.....)

在order by子句中，可以使用自定义排序，可以将expr中的数据按照指定的param1，2，3顺序排列。 不在param参数中的数据不会参与排序,将会放在最前面,可以使用asc，desc控制整体顺序。 如果有NULL值，可以使用nulls first，nulls last控制null的顺序

example

mysql> select k1,k7 from baseall where k1 in (1,2,3) order by field(k1,2,1,3);
+------+------------+
| k1   | k7         |
+------+------------+
|    2 | wangyu14   |
|    1 | wangjing04 |
|    3 | yuanyuan06 |
+------+------------+
mysql> select class_name from class_test order by field(class_name,'Suzi','Ben','Henry');
+------------+
| class_name |
+------------+
| Suzi       |
| Suzi       |
| Ben        |
| Ben        |
| Henry      |
| Henry      |
+------------+
mysql> select class_name from class_test order by field(class_name,'Suzi','Ben','Henry') desc;
+------------+
| class_name |
+------------+
| Henry      |
| Henry      |
| Ben        |
| Ben        |
| Suzi       |
| Suzi       |
+------------+
mysql> select class_name from class_test order by field(class_name,'Suzi','Ben','Henry') nulls first;
+------------+
| class_name |
+------------+
| null       |
| Suzi       |
| Suzi       |
| Ben        |
| Ben        |
| Henry      |
| Henry      |
+------------+

keywords

field