如何实现一个左外连接的实体框架

Question

我有以下SQL查询： -

select distinct * from dbo.Profiles profiles 
left join ProfileSettings pSet on pSet.ProfileKey = profiles.ProfileKey 
left join PlatformIdentities pId on pId.ProfileKey = profiles.Profilekey 

我需要将其转换为LinqToEntities表达。我试过以下内容： -

from profiles in _dbContext.ProfileSet 
          let leftOuter = (from pSet in _dbContext.ProfileSettingSet 
              select new 
                 { 
                  pSet.isInternal 
                 }).FirstOrDefault() 
select new 
             { 
              profiles.ProfileKey, 
              Internal = leftOuter.isInternal, 
              profiles.FirstName, 
              profiles.LastName, 
              profiles.EmailAddress, 
              profiles.DateCreated, 
              profiles.LastLoggedIn,            
             }; 

上面的查询工作正常，因为我没有考虑第三个表“PlatformIdentities”。单一的左外连接与我上面所做的一样。我如何包含PlatformIdentities（第三张表）？我基本上想要将我在本文开头指定的SQL查询（这正是我所需要的）转换为LinqToEntities。

感谢

Answer 1

让我知道，如果你要选择不同的东西，但真正加盟低于

from p in _dbContext.ProfileSet 
       join ps in _dbContext.ProfileSettings on p.ProfileKey = ps.ProfileKey into a 
       join pi in _dbContext.PlatformIdentities on p.ProfileKey = pi.ProfileKey into b 

       select new 
       { 
        profiles.ProfileKey, 
        profiles.FirstName, 
        profiles.LastName, 
        profiles.EmailAddress, 
        profiles.DateCreated, 
        profiles.LastLoggedIn, 
        PlatformSettings = a.Select(x=>x), 
        PlatformIdentities = b.Select(y=>y) 
       }