T-Sql查找重複的行值

Question

我想寫一個存儲過程。

在那個存儲過程中，我想從表中找到重複的行值，並計算這些行上的和操作到同一個表。

比方說，我有一個CustomerSales表;

ID SalesRepresentative Customer Quantity 
1 Michael    CustA  55  
2 Michael    CustA  10 

，我需要把表...

ID SalesRepresentative Customer Quantity 
1 Michael    CustA  65  
2 Michael    CustA  0 

當我發現在同一時間SalesRepresentative和Customer重複，我想總結這些行的所有Quantity值，並分配給一張桌子的第一排，其他人將是'0'。

你能幫助我嗎？

Answer 1

聚集重複到一行：

SELECT min(ID) AS ID, SalesRepresentative, Customer 
     ,sum(Quantity) AS Quantity 
FROM CustomerSales 
GROUP BY SalesRepresentative, Customer 
ORDER BY min(ID) 

或者，如果你真的想與0那些額外行作爲結果Quantity：

SELECT ID, SalesRepresentative, Customer 
     ,CASE 
      WHEN (count(*) OVER (PARTITION BY SalesRepresentative,Customer)) = 1 
      THEN Quantity 
      WHEN (row_number() OVER (PARTITION BY SalesRepresentative,Customer 
            ORDER BY ID)) = 1 
      THEN sum(Quantity) OVER (PARTITION BY SalesRepresentative,Customer) 
      ELSE 0 
     END AS Quantity 
FROM CustomerSales 
ORDER BY ID 

這使得大量使用的window functions。

替代版本，而窗函數：

SELECT min(ID) AS ID, SalesRepresentative, Customer, sum(Quantity) AS Quantity 
FROM CustomerSales 
GROUP BY SalesRepresentative, Customer 

UNION ALL 
SELECT ID, SalesRepresentative, Customer, 0 AS Quantity 
FROM CustomerSales c 
GROUP BY SalesRepresentative, Customer 
LEFT JOIN (
    SELECT min(ID) AS ID 
    FROM CustomerSales 
    GROUP BY SalesRepresentative, Customer 
    ) x ON (x.ID = c.ID) 
WHERE x.ID IS NULL 
ORDER BY ID