顯示每年的收入

Question

我正在使用NorthWind SQL數據庫。對於那些不熟悉的人，它有以下一些表格：

Orders, 
OrderDetails, 
Products, 
categories 
(Orders.OrderID = OrderDetails.OrderID) 
(Products.ProductID = OrderDetails.ProductID) 
(Categories.categoryID = Products.categoryID) 

Orders has a column named "OrderDate" (formatted as dd/mm/yy) 
OrderDetails has a column named "Price" 

我需要顯示每年的總收入。也就是所有「價格」的總和。任何想法如何做？

Answer 1

嘗試這樣的事情，因爲我們沒有完整的表格結構。 GROUP BY的這種方式適用於MySQL

SELECT SUM (OD.Price) AS Revenue FROM OrderDetails OD 
    INNER JOIN Orders O ON Orders.OrderID = OrderDetails.OrderID 
    GROUP BY YEAR(O.OrderDate);