相关疑难解决方法(0)

在C#中它会是这样的:

table
   .GroupBy(row => row.SomeColumn)
   .Select(group => group
       .OrderBy(row => row.AnotherColumn)
       .First()
   )

Linq-To-Sql将其转换为以下T-SQL代码:

SELECT [t3].[AnotherColumn], [t3].[SomeColumn]
FROM (
    SELECT [t0].[SomeColumn]
    FROM [Table] AS [t0]
    GROUP BY [t0].[SomeColumn]
    ) AS [t1]
OUTER APPLY (
    SELECT TOP (1) [t2].[AnotherColumn], [t2].[SomeColumn]
    FROM [Table] AS [t2]
    WHERE (([t1].[SomeColumn] IS NULL) AND ([t2].[SomeColumn] IS NULL))
      OR (([t1].[SomeColumn] IS NOT NULL) AND ([t2].[SomeColumn] IS NOT NULL)
        AND ([t1].[SomeColumn] = [t2].[SomeColumn]))
    ORDER BY [t2].[AnotherColumn]
    ) AS [t3]
ORDER BY [t3].[AnotherColumn]

但它与MySQL不兼容.

我有一个MySQL表,其值如下:

+--------------+
| user_email   |
+--------------+
| ab@gmail.com |
| cd@gmail.com |
| ef@yahoo.com |
| gh@yahoo.com |
| ij@gmail.com |
| kl@other.net |
+--------------+

我需要从此电子邮件地址列表中返回唯一域名列表,例如:

gmail.com,yahoo.com,other.net

到目前为止,我使用以下SQL语句来选择:

SELECT SUBSTRING_INDEX(user_email,'@',-1)

但是,这只解决了我的一半问题 - 它正在返回域名.使用DISTINCT没有做到这一点.我错过了什么？

仅供参考:这是在LAMP堆栈上运行.谢谢!