SQL 子查詢涉及計算涉及多表

Question

大家能告訴我如何將下面的 SQL 查詢轉換為子查詢嗎？ 我已經嘗試了很多次，但我仍然找不到解決方案。 謝謝你。

SELECT  
FARMER.Farmer_name AS "Farmer's Name",  
SUM((PRODUCE.Product_price * 0.5) * CART.Quantity * 15/100) AS "Profit Loss" 
FROM  
CART, PRODUCE, FARMER, PAYMENT, PURCHASE 
WHERE
PURCHASE.Order_date BETWEEN TO_DATE ('06/09/2020', 'DD/MM/YYYY') AND TO_DATE ('08/09/2020', 'DD/MM/YYYY') AND 
PAYMENT.Payment_status = 'Paid' AND 
CART.Order_id = PURCHASE.Order_id AND 
CART.Order_id = PAYMENT.Order_id AND 
PRODUCE.Farmer_id = FARMER.Farmer_id AND  
PRODUCE.Product_code = CART.Product_code AND 
PAYMENT.Order_id = PURCHASE.Order_id 
GROUP BY  
FARMER.Farmer_name 
ORDER BY  
"Profit Loss" DESC; 

Answer 1

如果你想創建一個帶有當前查詢返回的子查詢，那么如果你使用如下視圖：

CREATE VIEW view_name AS
//content of your query

然后像這樣調用視圖

SELECT * FROM view_name; //or any selection