クロスSQLクエリ

Question

CREATE TABLE [dbo].[Country](
     [Id] [int] NOT NULL, 
     [name] [varchar](50) NULL) 

    CREATE TABLE [dbo].[State](
     [Id] [int] NOT NULL, 
     [name] [varchar](50) NULL, 
      [CountryId] [int] NULL references Country(Id)) 

    CREATE TABLE [dbo].[City](
     [Id] [int] NOT NULL, 
     [name] [varchar](50) NULL, 
      [StateId] [int] NULL references State(Id)) 

Value in table 

国

------- 
1 USA 
2 UK 

州

----- 
1 NY 1 
2 NSW NULL 

市今

----- 
1 Sydney 2 
2 Mumbai NULL 
3 Delhi 1 

私はCity.Name、State.Name、Country.Nameリストが欲しいに参加NULL値もあります。

例えばシドニーNSW NULL デリーNY USA 避けレコード複製

私はそれで、このクエリしかし、いくつかミスをしてみてください：

SELECT  Country.name, City.Name AS Expr1, State.Name AS Expr2 
FROM   City CROSS JOIN 
         State CROSS JOIN 
         Country 
WHERE  (City.StateId IN 
          (SELECT  StateId 
           FROM   City AS City_1)) OR 
         (State.CountryId IN 
          (SELECT  CountryId 
           FROM   State AS State_1)) 

Answer 1

SELECT  C2.name, C.Name AS Expr1, S.Name AS Expr2 
FROM   City c 
LEFT OUTER JOIN State s ON c.stateid = s.id 
LEFT OUTER JOIN Country c2 on s.countryId = c2.id