LINQ到SQL - GROUP BY和計數

Question

我想這個查詢轉換（已工作）

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到SQL，但我不知道我做錯了。看看我的嘗試

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

我只需要對我的建築物進行分組並統計每個人有多少用戶。

Answer 1

只需使用的Count方法：

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