從不同的表

Question

我有一個表的客戶，和一張桌子推銷員獲取原始數據，內部都具有一個名稱列：

CustomerName  SalesmanName 
Peter    Charlie 
Vlado    Charlie 
Landon    Charlie 
Peter    Clint 
Vlado    Clint 
Landon    Clint 
Peter    Tim 
Vlado    Tim 
Landon    Tim 
Peter    Armand 
Vlado    Armand 
Landon    Armand 

但想要得到的是：

CustomerName   SalesmanName 
Peter     Charlie 
Vlado     Clint 
Landon     Tim 
         Armand 

我該怎麼辦？是否有可能使用查詢完全按照他們在表中的那些列來獲取這些列？

Answer 1

可以使用ROW_NUMBER()功能來生成連接兩個有用的任意行號：

;with cust AS (select name,ROW_NUMBER() OVER(ORDER BY name) AS RN from Customers) 
    ,sales AS (select name,ROW_NUMBER() OVER(ORDER BY name) AS RN from Salesman) 
select a.name as CustomerName 
    , b.name as SalesmanName 
from cust a 
FULL JOIN sales b 
    ON a.RN = b.RN 
ORDER BY COALESCE(a.RN,b.RN) 

Answer 2

我假設你有你的表的主鍵，那麼你可以通過使用ROW_NUMBER配對這兩列和FULL OUTER JOIN。可以說CustomerId和SalesmanId分別是Customers和Salesman表的主鍵。現在，這裏是查詢： -

SELECT 
    ISNULL(CS.Name, '') AS CustomerName, 
    ISNULL(SM.Name, '') AS SalesmanName 
FROM 
(
    SELECT 
     Name, 
     ROW_NUMBER() OVER (ORDER BY CustomerId) AS RN 
    FROM Customers 
) CS 
FULL OUTER JOIN 
(
    SELECT 
     Name, 
     ROW_NUMBER() OVER (ORDER BY SalesmanId) AS RN 
    FROM Salesman 
) SM 
ON SM.RN = CS.RN 

下面是結果

CustomerName   SalesmanName 
    Peter     Charlie 
    Vlado     Clint 
    Landon     Tim 
          Armand