Question

我在根据价格和奖品类别计算收入方面存在问题。这是电影院价格表：

Prices           
Movie              Regular        Student
Batman             8.50            7.50
Spiderman          6.50            6.00
The Godfather      5.50            4.50
.......

这是预订客户的表格：

Customers
Name            Movie         Date               Price
Dennis Jones    Batman      2014-12-01           Student
Al McGregor     Spiderman   2014-12-01           Regular
Lee Wong        Batman      2014-12-01           Regular
.......

基于此，如何使用SQL查询计算2014-12-01蝙蝠侠的未来收入？

汉克

Answer 1

这基本上是带有条件聚合的join：

select sum(case when price = 'Student' then Student
                when price = 'Regular' then Regular
           end)
from customers c join
     prices p
     on c.movie = p.movie
where date = '2014-12-01' and time = '1200' and Movie = 'Batman';

关于数据结构的评论。您的表应该有主键，通常是自动递增的整数，而不是使用字符串组合。正如您所做的那样，将日期和时间分开是没有问题的，尤其是对于像“时间”代表每天插槽的电影一样。

Answer 2

我可能会选择以下内容：

Select Movie, MovieDate, MovieTime, Sum(PriceToPay)
from
(Select P.Movie, P.Regular, P.Student, C.Name, C.Date as MovieDate, C.Time as MovieTime, (Case  when C.Price = 'Student' then P.Student else P.Regular end) as PriceToPay
from Prices P inner join Customer C on P.Movie = C.Movie) xxx
Group by Movie, MovieDate, MovieTime

SQL：基于价格类别的总和价格

2 个答案: