我有以下表格:
Suppliers(Sno, Sname, Address)
Parts(Pno, Pname, Colour)
Catalogue(Sno, Pno, Price)
我希望找到供应各个部分的供应商的Sno。
到目前为止,我写过:
SELECT s.sname
FROM suppliers s JOIN catalogue c
USING s.sno
现在我如何编写“供应每个部分的供应商”部分?
我正在考虑为每个供应商Sno提供来自parts = count(pno)的count(*)。有人可以给我一个提示/写下平等的第一部分吗?
谢谢!
答案 0 :(得分:2)
你很亲密。您需要使用子查询添加/ by子句组:
group by s.sname having count(*) = (select count(*) from catalogue)
答案 1 :(得分:2)
离开我的头顶,你可以写
SELECT s.Sno
FROM suppliers s
WHERE NOT EXISTS (
SELECT p.Pno
FROM parts p
WHERE NOT EXISTS (
SELECT c.*
FROM catalogue c
WHERE c.Pno = P.Pno
AND c.Sno = S.Sno
)
)
即。供应商不存在(我们不提供的部分),以避免计数的解决方案。不知道这是否比计数更有效或更低效。
答案 2 :(得分:2)
SELECT s.sname
FROM suppliers s
INNER JOIN catalogue c
ON s.Sno = c.Sno
GROUP BY s.sname
HAVING COUNT(c.Pno) = (SELECT COUNT(Pno) FROM Parts)
答案 3 :(得分:0)
SELECT s.Sno, s.Sname
FROM Suppliers s
CROSS JOIN Parts p
LEFT JOIN Catalogue c ON s.Sno = c.Sno AND p.Pno = c.Pno
GROUP BY s.Sno, s.Sname
HAVING COUNT(*) = COUNT(c.Pno)
答案 4 :(得分:0)
试试这个:
alter proc clr
@c char(10),
@pno int output
as
begin
declare @f int
if exists(select p# from p where colour=@c)
begin
select @pno=p# from p where colour=@c
--set @f=1
end
-- else
-- set @f=0
-- return @f
end
--clr 'red',2
select p# from p where colour='red'
alter proc prcs
@c char(20)
as
begin
declare @pno numeric(2)
declare @f int
exec @f=clr @c,@pno output
--if @f=1
-- begin
select @pno
select s# from sp where p#=@pno
--set @i=1
-- end
--set @i=0
--return @i
end
prcs 'red'
select * from sp
select * from p,sp where p.p#=sp.p# and colour='red'
alter proc prcj
@c char(10)
as
begin
declare @i int
exec @i=prcs @c
if @i=1
begin
print'list of supplier'
select sname from s
where s#=@c
end
else
print'this record is not found'
end