我需要创建显示如下所示收入的视图。 (游乐园数据库)
我有3张桌子:x_transaction(transaction_id,rides_id,金额等)x_rides(rides_id,rides_category_id,...)
x_rides_category(rides_category_id,名称,...)而且我需要创建一个视图来显示每个游乐设施类别的总收入
类别收入------------ ---------------运动34000水27000肾上腺素24300成人[null
顺便说一句,抱歉我的英语不好。
CREATE VIEW RIDE_CATEGORY_REVENUE_VIEW AS
SELECT c.NAME AS CATEGORY, SUM(t.AMOUNT) AS REVENUE
FROM X_RIDES_CATEGORY c
INNER JOIN X_RIDES r
ON r.RIDES_CATEGORY_ID = c.RIDES_CATEGORY_ID
INNER JOIN X_TRANSACTION t
ON t.RIDES_ID = r.RIDES_ID
我询问X_TRANSACTION上第二个字段的名称是RIDE_ID还是RIDES_ID。后者与X_RIDES上的对应字段匹配,但是我使用了名字,因为这就是您在X_RIDES表摘要中显示的名称。
Create view your_view_name as
Select cat.name as category, sum(amount) as revenue
From x_rides_category cat
Left join x_rides r on cat.rides_category_id = r.rides_category_id
Left join x_transaction t on r.rides_id = t.rides_id
Group by cat.name
干杯!