聚合功能与分区

Question

我需要添加一个额外的列，将获得总销售额％。我试图这样做，加入：

Book_sales/SUM(Book_sales) As 'Total_Sales%' 

但是，这是行不通的。因为这是一个聚合函数，SQL需要，我会组publ_id我不想做

Answer 1

，我认为你应该加入与分组查询与汇总查询：

SELECT 
    .... 
    OD.Quantity*OD.Order_price/SUM_OD.Book_Total As 'Total_Sales%'  
    .... 

FROM Books AS BKS 
INNER JOIN order_details AS OD ON BKS.book_id=OD.book_id 
INNER JOIN 
    (SELECT book_id, 
      SUM(Quantity*Order_price) as Book_Total 
    FROM order_details 
    GROUP BY book_id 
) AS SUM_OD ON BKS.book_id=SUM_OD.book_id