Question

3.21考虑图3-21中的图书馆数据库。用SQL写出如下查询：

Answer 1

select name from member,book,borrowed where member.memb_no=borrowed.memb_no and book.isbn=borrowed.isbn and borrowed.publisher="xxx"

select name from member where memb_no in (select memb_no from borrowed group by memb_no having count(*) = (select count(*) from book where publisher="xxx"))

select name,publisher from member,borrowed,book group by name,publisher where member.memb_no=borrowed.memb_no

and

book.isbn=borrowed.isbn

having

count(*)>5

select(select count(*) from borrowed)/ (select count(*)from member)

我没有数据， 所以凭空写的， 思路差不多这样吧。有问题私信我吧. 你的列有关键字name，如果是mysql的话加``，sqlserver加[]。