Question

我有这张表：

tblDiving(
diving_number int primary key
diving_club int
date_of_diving date)

tblDivingClub(
number int primary key not null check (number>0),
name char(30),
country char(30))

tblWorks_for(
diver_number int
club_number int
end_working_date date)

tblCountry(
name char(30) not null primary key)

我需要写一个查询来返回一个国家的名称和其中的“超级俱乐部”的数量。超级俱乐部是一个俱乐部，拥有超过25名工作潜水员（tblWorks_for.end_working_date为空）或去年有超过100名潜水员（tblDiving）。在我获得国家和超级俱乐部的数量之后，我只需要展示包含超过2个超级俱乐部的国家。

我写了这两个问题：

select tblDivingClub.name,count(distinct tblWorks_for.diver_number) as number_of_guids
from tblWorks_for 
inner join tblDivingClub on tblDivingClub.number = tblWorks_for.club_number,tblDiving
where tblWorks_for.end_working_date is null
group by tblDivingClub.name

select tblDivingClub.name, count(distinct tblDiving.diving_number) as number_of_divings
from tblDivingClub
inner join tblDiving on tblDivingClub.number = tblDiving.diving_club
WHERE tblDiving.date_of_diving <= DATEADD(year,-1, GETDATE())
group by tblDivingClub.name

但我不知道如何继续。每个查询都单独工作，但我如何组合它们并从中进行选择？这是大学任务，我不允许使用观点或临时表。

这是我的第一个程序，所以我不确定我在做什么：）

Answer 1

WITH CTE AS (

select tblDivingClub.name,count(distinct tblWorks_for.diver_number) as diving_number
from tblWorks_for 
inner join tblDivingClub on tblDivingClub.number = tblWorks_for.club_number,tblDiving
where tblWorks_for.end_working_date is null
group by tblDivingClub.name

UNION ALL

select tblDivingClub.name, count(distinct tblDiving.diving_number) as diving_number
from tblDivingClub
inner join tblDiving on tblDivingClub.number = tblDiving.diving_club
WHERE tblDiving.date_of_diving <= DATEADD(year,-1, GETDATE())
group by tblDivingClub.name
)

SELECT * FROM CTE

只要每个查询中的列数相同，您就可以使用UNION ALL组合查询。然后，您可以将它们滚动到公用表表达式（CTE）中并从中进行选择。

从多个查询中选择

1 个答案: