SQL(MySQL)中是否有办法在特定字段上执行"循环"ORDER BY？

Question

SQL(MySQL)中是否有办法在特定字段上执行"循环"ORDER BY？

举个例子,我想拿一个像这样的表:

+-------+------+
| group | name |
+-------+------+
|     1 | A    |
|     1 | B    |
|     1 | C    |
|     2 | D    |
|     2 | E    |
|     2 | F    |
|     3 | G    |
|     3 | H    |
|     3 | I    |
+-------+------+

并运行以此顺序生成结果的查询:

+-------+------+
| group | name |
+-------+------+
|     1 | A    |
|     2 | D    |
|     3 | G    |
|     1 | B    |
|     2 | E    |
|     3 | H    |
|     1 | C    |
|     2 | F    |
|     3 | I    |
+-------+------+

请注意,该表可能有很多行,因此我无法在应用程序中进行排序.(我在查询中显然也有一个LIMIT子句).

Answer 1

我会尝试这样的事情:

SET @counter = 0;
SELECT (@counter:=@counter+1)%3 as rr, grp, name FROM table ORDER by rr, grp 

Answer 2

你可以做的是创建一个临时列,你在其中创建集合,给你这样的东西:

+-------+------+-----+
| group | name | tmp |
+-------+------+-----+
|     1 | A    |   1 |
|     1 | B    |   2 |
|     1 | C    |   3 |
|     2 | D    |   1 |
|     2 | E    |   2 |
|     2 | F    |   3 |
|     3 | G    |   1 |
|     3 | H    |   2 |
|     3 | I    |   3 |
+-------+------+-----+

要了解如何创建集合,请查看此问题/答案.

然后它很简单

ORDER BY tmp, group, name