select jno from p,spj where color = '红' and sno in (select sno from s where city = '天津')
select jno from spj where pno in (select pno from p where color = '红') and sno in (select sno from s where city = '天津')
这两条语句有什么区别，为什么查询结果不一样？

我想知道如何在sql上打开已建的表😂