SQL表連接查詢

Question

我在SQL 3個表

1. ProductMaster與列產品名稱
2. 購買數據與列產品名稱和數量
3. SaleData與列產品名稱和數量

請指引我爲表連接寫查詢得到如下結果

PRODUCT1 10 5  5 
PRODUCT2 10 0  10 
PRODUCT3 10 5  5 

Answer 1

您不再需要ProductMaster表，因爲你需要的所有信息都在購買數據和SALEDATA

SELECT P.[ProductName] as ProductName, P.PurchaseQty, S.SalteQTY, P.purchaseQTY-S.SalteQTY as ClosingQty 

    FROM [PURCHASEDATA] P LEFT OUTER JOIN [SALEDATA] S ON P.ProductName=S.ProductName 

Answer 2

嘗試開始是這樣的：

SELECT [ProductMaster].[ProductName] 
    ,[PurchaseData].[Quantity] AS [PurchasedQuantity] 
    ,[SaleData].[Quantity]  AS [SoldQuantity] 
    ,[PurchaseData].[Quantity] 
     - [SaleData].[Quantity] AS [ClosingStock] 
    FROM [ProductMaster] 
    LEFT OUTER JOIN [PurchaseData] 
     ON [ProductMaster].[ProductName] = [PurchaseData].[ProductName] 
    LEFT OUTER JOIN [SaleData] 
     ON [ProductMaster].[ProductName] = [SaleData].[ProductName] 

的想法是有主表和聯接兩個從屬表到主用INNER JOIN在產品名稱字段。