mysql - 如何在MySQL中为每个组选择第一行？

在C#中将是这样的:

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]

但是它与MySQL不兼容。

最佳答案

我的答案仅基于您的帖子标题，因为我不了解C#，也不了解给定的查询。但是在MySQL中，我建议您尝试子选择。首先获取一组有趣的列的主键，然后从这些行中选择数据:

SELECT somecolumn, anothercolumn
  FROM sometable
 WHERE id IN (
               SELECT min(id)
                 FROM sometable
                GROUP BY somecolumn
             );