1
Suppliers(sid: integer, sname: string, address: string)
Parts(pid: integer, pname: string, color: string)
Catalog(sid: integer, pid: integer, cost: real)
找到供應商每個零件的供應商名稱?之間的差異不存在,除了在sql中
select s.sname
from suppliers s
where NOT EXISTS (select p.pid
from parts p
where p.color='red' and
NOT EXISTS (select c.pid from parts p where c.pid=p.pid and c.sid=s.sid and p.color='red'
)
)
此回答的內容可能不正確?
你有預期的結果中的所有行?有錯誤嗎? – 2014-10-22 00:05:55