为什么生成的 EF 6.4 SQL 有问题？

Question

我有一个看起来像这样的查询。 UserId 是随机字母串。 searchCritera 是要搜索的模型。 searchCriteria.MainRoleValueList 包含搜索的角色（枚举）

var criteria = DBContext.People.Include(w => w.Main).AsQueryable();

//A lot of code that doesnt affect this senario.

if (!string.IsNullOrEmpty(searchCriteria.UserIdLike))
{
     criteria = criteria.Where(i => i.UserId.Contains(searchCriteria.UserIdLike));
}
if (searchCriteria.MainRoleValueList != null && searchCriteria.MainRoleValueList.Count > 0)
{
         var MainMembership = DBContext.MainMemberships.Where(p => searchCriteria.MainRoleValueList.Contains(p.MainRoleValue) && p.ValidTo == null).Join(criteria,
                        main => new { main.UserId, main.Main_Id }, current => new { current.UserId, current.Main_Id }, (main, current) => main);

var tmp = MainMembership.ToList(); //Added line to trigger communication with SQL server
}

生成的sql代码为

SELECT 
    [Extent1].[Id] AS [Id], 
    [Extent1].[UserId] AS [UserId], 
    [Extent1].[Main_Id] AS [Main_Id], 
    [Extent1].[MainRoleValue] AS [MainRoleValue], 
    [Extent1].[ValidFrom] AS [ValidFrom], 
    [Extent1].[ValidTo] AS [ValidTo]
    FROM  [dbo].[MainRoleMembership] AS [Extent1]
    INNER JOIN [dbo].[Person] AS [Extent2] ON ([Extent1].[UserId] = [Extent2].[UserId]) AND ([Extent1].[Main_Id] = [Extent2].[Main_Id])
    WHERE ([Extent1].[MainRoleValue] IN (300, 400, 200, 410)) AND ([Extent1].[ValidTo] IS NULL) AND (([Extent2].[FullName] LIKE '%rty12tt%' ESCAPE N'~') 
    OR ([Extent2].[UserId] LIKE '%rty12tt%' ESCAPE N'~')) AND 
    ( EXISTS (SELECT 
        1 AS [C1]
        FROM  ( SELECT 1 AS X ) AS [SingleRowTable1]
        WHERE 1 = 0
    ))

除了最后一部分，它还有效

EXISTS (SELECT 
        1 AS [C1]
        FROM  ( SELECT 1 AS X ) AS [SingleRowTable1]
        WHERE 1 = 0

为什么要添加这个？因为它删除了我想要的正确结果。如果我删除那部分和运行 SQL 服务器上的查询，我就会得到我想要的用户。我应该如何重写我的查询以便不包括在内？

已添加：是的，具有 UserId 的两个表没有外键用户身份。这是系统中的一个糟糕设计，但我暂时无法修复。

已添加：在表之间为 UserId 添加了一个外键，但没有帮助

Answer 1

我添加了一个空列表并进行了比较..这就是为什么

EXISTS (SELECT 
        1 AS [C1]
        FROM  ( SELECT 1 AS X ) AS [SingleRowTable1]
        WHERE 1 = 0

已添加。为列表添加了计数检查，问题消失了

为什么生成的 EF 6.4 SQL 有问题？

Why is the EF 6.4 generated SQL faulty?

sql

entity-framework

linq-to-entities