計算總銷售額增值稅

Question

我需要計算總銷售額的總增值稅額（總銷售額的15％）。 IM與此查詢掙扎我第一次嘗試了選擇和隨後沒有工作 - >

SELECT SUM(price) AS total_sales, 
     SUM(price) * 0.15 AS fifteen_percent 
FROM sales; 

這裏是產品表

這裏的圖片銷售的圖片表

任何幫助將不勝感激！，謝謝。

Answer 1

SELECT SUM(price*quantity) AS total_sales, 
     SUM(price*quantity) * 0.15 AS fifteen_percent 
FROM sales 
JOIN products ON sales.prod_id = products.prod_id; 

Answer 2

Wawrzyniec是正確的，但您也可以使用窗口函數進行聚合。

  SELECT DISTINCT prod_name, 
          SUM(price) OVER(PARTITION BY prod_name) * quantity as total_sales, 
          (SUM(price) OVER(PARTITION BY prod_name) * quantity) * 0.15 as fifteen_percent  
      FROM sales 
      INNER JOIN products ON sales.prod_id = products.prod_id;