我怎麼能組減計數？

Question

我有Orderdetails表，其中包含訂單的詳細信息，我需要計算每個產品的銷售額減去每個產品退還（返回）的訂單。

ex: total sales of product = sales orders total - returned orders of a product 

注意：我使用了事務類型字段，以便我可以過濾訂單類型。

訂單明細表字段。

ID - Productname - Price - ono - transaction_type 
11 - prod1  - 100.00- 1 - salesorder 
12 - prod2  - 200.00- 2 - salesorder 
13 - prod1  - 100.00- 1 - returned 
14 - prod2  - 200.00- 3 - salesorder 
15 - prod2  - 200.00- 4 - salesorder 

我問

Productname - Total sales 
Prod1  - 0 
Prod2  - 3 

Answer 1

你可以嘗試這樣什麼---

Select Product_NAME, Sum(Case when transaction_type='salesorder' then 1 Else 0 End)- Sum(Case when transaction_type!='salesorder' then 1 Else 0 End) as TotalSale 
from OrderDetals group by Product_NAME 

Answer 2

試試這個！

SELECT ProductName, 
SUM(CASE WHEN [transaction_type] = 'salesorder' THEN [Quentity] ELSE -1 * [Quentity] END) AS [Total Number Of Sale] 
FROM your_table)name 
GROUP BY ProductName