SQL面试笔试经典题(Part 2)

本文是在Cat Qi的原贴的基础之上，经本人逐题分别在MySql数据库中实现的笔记.

参考原贴：http://www.cnblogs.com/qixuejia/p/3637735.html 

01 问题描述

本题用到下面三个关系表：

借书卡：card

cno	name	class
卡号	姓名	班级

 图书：books

bno	bname	author	price	quantity
书号	书名	作者	单价	库存册数

借书记录：borrow

cno	bno	rdate
借书卡号	书号	还书日期

备注：限定每人每种书只能借一本；库存册数随借书、还书而改变。

02 问题及SQL实现

1、写出建立card,books,borrow表的SQL语句，要求定义表borrow的主码完整性约束和引用完整性约束

drop table if exists books;
create table books (
  bno int(11) auto_increment ,
  bname varchar(30) default null,
  author varchar(30) default null,
  price float(6,2) default null,
  quantity int(11) default null,
  primary key (bno)
) engine=innodb default charset=utf8;

drop table if exists card;
create table card (
  cno int(11) auto_increment,
  name varchar(30) default null,
  class varchar(30) default null,
  primary key (cno)
) engine=innodb default charset=utf8;

drop table if exists borrow;
create table borrow (
  cno int(11) not null,
  bno int(11) not null,
  rdate datetime null default current_timestamp,
  primary key (cno,bno),
  key bno (bno),
  constraint bno foreign key (bno) references books (bno),
  constraint cno foreign key (cno) references card (cno)
) engine=innodb default charset=utf8;

插入测试数据：

insert into card(name,class) values('张三','计科一班');
insert into card(name,class) values('李四','计科一班');
insert into card(name,class) values('王五','计科二班');
insert into card(name,class) values('六四','计科二班');
insert into card(name,class) values('七七','软工一班');
insert into card(name,class) values('粑粑','软工二班');

insert into books(bname,author,price,quantity) values ('水浒','施耐庵',188,3);
insert into books(bname,author,price,quantity) values ('计算机网络','谢希仁',49,3);
insert into books(bname,author,price,quantity) values ('计算方法','严蔚敏',58,3);
insert into books(bname,author,price,quantity) values ('计算方法习题集','殷人昆',188,3);
insert into books(bname,author,price,quantity) values ('数据库技术及应用','王珊',38,3);
insert into books(bname,author,price,quantity) values ('组合数学','周伟',28,3);
insert into books(bname,author,price,quantity) values ('redis初探','周成龙',25,3);

insert into borrow(cno,bno) values(1,1);
insert into borrow(cno,bno) values(2,1);
insert into borrow(cno,bno) values(3,1);
insert into borrow(cno,bno) values(4,3);
insert into borrow(cno,bno) values(4,6);
insert into borrow(cno,bno) values(5,6);
insert into borrow(cno,bno) values(2,7);

2、找出借书多于1本的读者,输出借书卡号及所借图书册数

select cno as "卡号",count(*) as "借书册数" 
from borrow 
group by cno 
having count(cno)>1;

3、查询借阅了"水浒"一书的读者，输出姓名及班级 

select c.name as "姓名",c.class as "班级"
from card c
where c.cno in 
(
    select br.cno from borrow br join books bs 
    on br.bno = bs.bno and bs.bname="水浒"
);

4、查询过期未还图书，输出借阅者（卡号）、书号及还书日期

select cno as "卡号",bno as "书号",rdate as "还书日期"
from borrow 
where rdate< now();

5、查询书名包括"网络"关键词的图书，输出书号、书名、作者 

select bno,bname,author from books where bname like "%网络%";

6、查询现有图书中价格最高的图书，输出书名及作者 

select bname,author 
from books 
where price = (select max(price) from books);

7、查询当前借了"计算方法"但没有借"计算方法习题集"的读者，输出其借书卡号，并按卡号降序排序输出 

select bo.cno
from borrow bo, books 
where bo.bno = books.bno and books.bname ="计算方法" and not exists
(
    select * from borrow r,books b where r.bno = b.bno and b.bname="计算方法习题集"
)
order by bo.cno desc;

8、将"计科一班"班同学所借图书的还期都延长一周

update borrow set rdate=adddate(rdate,INTERVAL 7 day)
where cno in (select cno from card where class="计科一班");

9、从books表中删除当前无人借阅的图书记录

delete from books where bno not in
(select distinct bno from borrow );

这里有3本图书被删除，只剩下1、3、6、7，执行删除操作后重新插入books表的原始数据以便做后面的题目。

10、如果经常按书名查询图书信息，请建立合适的索引

create index idx_books_name on books(bname);
--关于索引的使用参考:
--https://zhidao.baidu.com/question/492877300.html

11、在borrow表上建立一个触发器，完成如下功能：如果读者借阅的书名是"数据库技术及应用"，就将该读者的借阅记录保存在borrow_save表中（注borrow_save表结构同borrow表）

create view v_borrow
as 
select c.name,b.bname
from card c,books b,borrow r
where c.cno=r.cno and b.bno=r.bno and c.class="计科一班";

12、查询当前同时借有"计算方法"和"组合数学"两本书的读者，输出其借书卡号，并按卡号升序排序输出  

select b.cno
from borrow b
where b.bno in (select bno from books where bname in ("计算方法","组合数学"))
group by b.cno
having count(b.bno)=2
order by b.cno ;

13、假定在建books表时没有定义主键，写出为books表追加定义主键的语句

alter table books add primary key (bno);

14、为card表增加1列deptname（系名），可变长，最大50个字符 

alter table card add deptname varchar(50);

THE END.