linq到sql中的左外部联接3个表

我试图在linq中编写一个查询，在这里我加入了3个选项卡，并用字符串“ANY”填充空值，但这并没有发生。需要一些帮助，请告诉我，我在这方面是新手

我试过这样做

var results = from user in allusers
              join building in allbuildings where building.buildingid equals user.buildingid
              into BuildingAndUsers.FirstorDefault(new allbuildings{BuildingName="ANY" BuildingID=0})
              from blah in BuildingAndUsers
              join Site in AllSites where ....

比如：

var results = 
      from user in allusers
      join building in allbuildings on building.buildingid equals user.buildingid
          into BuildingAndUsers 
      from buildingAndUser in BuildingAndUsers.DefaultIfEmpty(new allbuildings { BuildingName="ANY", BuildingID=0 })
      join Site in AllSites on ....
          into BuildingAndUsersAndSites
      from buildingAndUsersAndSite in BuildingAndUsersAndSites.DefaultIfEmpty()
      select ...

---

酷这是工作。。。现在，我还需要向其余的联接添加默认值。我该如何做呢？有什么帮助吗？@VishweshwarKapse：与第一个联接的方式相同，没有其他任何问题。@VishweshwarKapse：如果答案解决了问题，请将其标记为