LINQ to Entities - DISTINCT在一列 [英] LINQ to Entities - DISTINCT on one column

问题描述

  SELECT DISTINCT Column1 
 FROM Table1 
  

我正在使用Entity Framework 4.当然，我不想使用Distinct方法来从数据库中提取数据后过滤数据。

谢谢， Pawel

解决方案

使用类似

  db.Table1.Select（t => t.Column1）.Distinct（）
  

正如Munim在他的评论中提到的，Distinct（）方法确实将DISTINCT添加到查询中。所以结果SQL查询将是

  SELECT [Distinct1]。[Column1] AS [Column1] 
 FROM（SELECT DISTINCT 
 [Extent1]。[Column1] AS [Column1] 
 FROM [dbo]。[Table1] AS [Extent1] 
）AS [Distinct1] 
  

Is there a way to write following query with Linq to Entities (or Entity SQL, or Method Syntax, or any other way, but I would like to achieve it with Linq to Entities):

SELECT DISTINCT Column1
FROM Table1

I'm using Entity Framework 4. Of course I don't want to use Distinct method that filters data after data is fetched from database.

thanks,Pawel

解决方案

Use something like

db.Table1.Select(t => t.Column1).Distinct()

As Munim mentioned in his comment, the Distinct() method does add the DISTINCT to the query. So resulting SQL query will be

SELECT [Distinct1].[Column1] AS [Column1]
  FROM ( SELECT DISTINCT 
    [Extent1].[Column1] AS [Column1]
    FROM [dbo].[Table1] AS [Extent1]
  )  AS [Distinct1]

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