Linq to SQL – Group By和Count

我正在尝试转换此查询（已经工作）

SELECT Building.NAME, COUNT([User].ID) FROM BuildingUser INNER JOIN Building ON Building.ID = BuildingUser.ID_BUILDING INNER JOIN [User] ON [User].ID = BuildingUser.ID_USER GROUP BY Building.NAME 

要Linq to SQL，但我不知道我做错了什么。 看看我的尝试

 from buildinguser in db.GetTable() join building in db.GetTable() on buildinguser.ID_BUILDING equals building.ID join user in db.GetTable() on buildinguser.ID_USER equals user.ID group building by building.NAME into grpBuilding select new { building = grpBuilding.Key, users = }; 

我只需要对我的建筑物进行分组，并计算每个建筑物的用户数量。

Answer 1

只需使用Count方法：

 from buildinguser in db.GetTable() join building in db.GetTable() on buildinguser.ID_BUILDING equals building.ID join user in db.GetTable() on buildinguser.ID_USER equals user.ID group building by building.NAME into grpBuilding select new { building = grpBuilding.Key, users = grpBuilding.Count() };