sql – 除特定值以外的组

我正在尝试创建一个(sqlite)查询,该查询将执行GROUP BY,但不会将值为’unkNown’的任何内容进行分组.例如,我有表：

id |   name  | parent_id | school_id |
 1 | john    |   1       |    1      |
 2 | john    |   1       |    1      |
 3 | john    |   1       |    1      |
 4 | nick    |   2       |    2      |
 5 | nick    |   2       |    2      |
 6 | nick    |   3       |    3      |
 7 | bob     |   4       |    4      |
 8 | unkNown |   5       |    5      |
 9 | unkNown |   5       |    5      |
 10| unkNown |   5       |    5      |

通过’GROUP BY name,parent_id,school_id’的正确查询,我需要返回以下行：

id |   name  | parent_id | school_id |
 1 | john    |   1       |    1      |
 3 | nick    |   2       |    2      |
 4 | nick    |   3       |    3      |
 5 | bob     |   4       |    4      |
 6 | unkNown |   5       |    5      |
 7 | unkNown |   5       |    5      |
 8 | unkNown |   5       |    5      |

任何帮助将不胜感激.谢谢！

解决方法

您不能轻易地使用一个语句执行此操作,但您可以UNION两个语句的结果

> GROUP列出所有未知的列表
>添加(UNION)所有未知的列表

sql语句

SELECT MIN(id),name,school_id
FROM   YourTable
WHERE  name <> 'unkNown'
GROUP BY
       name,school_id
UNION ALL
SELECT id,school_id
FROM   YourTable
WHERE  name = 'unkNown'

请注意,我假设您在结果中发布了错误的未知ID