datetime,primary key(CNO,BNO)); 2． 找出借书超过5本的读者,输出借书卡号及所借图书册数。 Select CNO,number=count(*) from BORROW group by CNO having count(*)>5; 3． 查询借阅了"水浒"一书的读者，输出姓名及班级。 Select NAME,CLASS from CARD c where exist (select * from BORROW b1,BOOK b2 where b1.BND=b2.BND and b2.name = ‘水浒’ and a.CNO=b2.CNO); 4． 查询