我需要两张桌子的产品库存数量

Question

我有两张桌子：

1. product_in（存储所有产品数量）

   Product Code(PK)     Description                QTY
   RS121102             SUITS                      100
   RS129985             SUITS                      100
   DF-C09               SHIRTS                     50
   AE-H05               SHIRTS                     50
   

2. product_out（存储所有售出的产品数量）

   Product Code         Description                QTY
   RS121102             SUITS                      50
   AE-H05               SHIRTS                     10
   

我想要下面的结果

Product Code         Description        Total Qty        Sold QTY
RS121102             SUITS                  100            50
RS129985             SUITS                  100            0
DF-C09               SHIRTS                 50             0
AE-H05               SHIRTS                 50             10

我该怎么做？

Answer 1

SELECT pi.ProductCode, pi.Description, pi.QTY AS TotalQty, 
ISNULL(po.QTY, 0) AS SoldQty
FROM product_in as pi
LEFT JOIN product_out as po
ON po.ProductCode = pi.ProductCode

假设product_out中的每个产品都没有多条记录。

Answer 2

试试这个：

SELECT ProductCode, Description, SUM(Total_QTY) AS Total_Qty, SUM(Sold_Qty) AS Sold_Qty
FROM 
(
     SELECT ProductCode, Description, QTY As Total_Qty, 0 As Sold_Qty
     from product_in
)
UNION ALL
(
     SELECT ProductCode, Description,  -QTY As Total_Qty, QTY As Sold_Qty
     from product_out
)
GROUP BY ProductCode, Description