sql - 如何在子查询内应用两个 where 条件，另一个在子查询外应用？

Question

找到在单个电影租赁上花费低于 3 美元但总花费超过 15 美元的客户？

我写的查询如下

SELECT CustomerID,Customer.CustomerFirstName,Customer.CustomerSurname,Total FROM (SELECT DISTINCT Customer.CustomerID,Customer.CustomerFirstName,Customer.CustomerSurname,sum(([Rental].[Quantity])*([Film].[FilmPrice])) AS Total
FROM Film RIGHT JOIN (Customer INNER JOIN Rental ON Customer.CustomerID = Rental.CustomerIDFk) ON Film.FilmID = Rental.FlimIDFk 
GROUP BY Customer.CustomerID,Customer.CustomerFirstName,Customer.CustomerSurname) T WHERE  Total>15;

现在我该如何应用第二个条件，即 FilmPrice<3 请帮帮我。

这是 ERD 谢谢

Answer 1

只需在子查询中添加另一个 where 子句，在您加入之后但在 group by for 之前WHERE FilmPrice<3

Answer 2

您想找到他们租用的电影的最高价格小于 3 并且他们租用的所有电影的总价格大于 15 的客户。

像这样的东西：

SELECT CustomerID,
       CustomerFirstName,
       CustomerSurname
FROM   Customer
WHERE  CustomerId IN (
  SELECT r.CustomerIDFk
  FROM   Rental r
         INNER JOIN Film f
         ON ( f.FilmId = e.FilmIdFk )
  GROUP BY r.CustomerIdFk
  HAVING MAX(f.FilmPrice) < 3
  AND    SUM(f.FilmPrice * r.Quantity)>15
)