SQL＆QUOT;不＆QUOT;语法实体框架4.1 [英] SQL "not in" syntax for Entity Framework 4.1

问题描述

我有实体框架语法一个简单的问题，为不是在SQL等价的。从本质上讲，我想下面的SQL语法转换成实体框架语法：

I have a simple issue with Entity Framework syntax for the "not in" SQL equivalent. Essentially, I want to convert the following SQL syntax into Entity Framework syntax:

select  ID
from    dbo.List
where   ID not in (list of IDs)

下面是我用于查找单个记录的方法：

Here is a method that I use for looking up a single record:

public static List GetLists(int id)
{
    using (dbInstance db = new dbInstance())
    {
        return db.Lists.Where(m => m.ID == id);
    }
}

下面是一个伪的方法，我想用这个：

Here is a pseudo-method that I want to use for this:

public static List<List> GetLists(List<int> listIDs)
{
    using (dbInstance db = new dbInstance())
    {
        return db.Lists.Where(**** What Goes Here ****).ToList();
    }
}

谁能给我指针作为在其中，子句地区发生的事情？我看了这个一些论坛，并且看到了。载有（）或。任何（），但没有提及例子是一个足够接近配合。

Can anyone give me pointers as to what goes in the Where clause area? I read some forums about this and saw mention of using .Contains() or .Any(), but none of the examples were a close enough fit.

推荐答案

给这个一去...

public static List<List> GetLists(List<int> listIDs)
{
    using (dbInstance db = new dbInstance())
    {
        // Use this one to return List where IS NOT IN the provided listIDs
        return db.Lists.Where(x => !listIDs.Contains(x.ID)).ToList();

        // Or use this one to return List where IS IN the provided listIDs
        return db.Lists.Where(x => listIDs.Contains(x.ID)).ToList();
    }
}

这些将变成约以下数据库查询：

These will turn into approximately the following database queries:

SELECT [Extent1].*
FROM [dbo].[List] AS [Extent1]
WHERE  NOT ([Extent1].[ID] IN (<your,list,of,ids>))

或

SELECT [Extent1].*
FROM [dbo].[List] AS [Extent1]
WHERE  [Extent1].[ID] IN (<your,list,of,ids>)

分别。

这篇关于SQL＆QUOT;不＆QUOT;语法实体框架4.1的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！