How to select the first row for each group in MySQL?

Posted by Jader Dias on Stack Overflow See other posts from Stack Overflow or by Jader Dias
Published on 2010-04-29T17:36:27Z Indexed on 2010/04/29 17:47 UTC
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In C# it would be like this:

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

Linq-To-Sql translates it to the following T-SQL code:

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]

But it is uncompatible with MySQL.

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