数据库实验二报告

实验二 简单查询及子查询

一. 目的：

练习SQL.

二. 内容：

1. 练习查询语句:（Example3.4.1-3.4.3; Example3.4.6-3.4.14； Example3.5.1.-3.5.2). 操作内容截图如下：

CUSTOMERS :

AGENTS:

PROODUCTS:

ORDER;

2练习查询语句

Example3.4.4

select distinct cid from orders

where aid in (select aid from agents where city='Duluth' or city='Dallas');

Example3.4.2 Retrieve all information concerning agents based in Duluth or Dallas. select * from agents

where city in('Duluth','Dallas');

Example3.4.3

select cname,discnt from customers

where cid in(select cid from orders where aid in(select aid from agents where city in('Duluth','Dallas')));

Example3.4.6

select ordno from orders x where exists (select cid,aid from customers c,agents a

where c.cid=x.cid and a.aid=x.aid and c.city='Duluth' and a.city='New York);

Example3.4.7

select aid from agents where commission<=all (select commission from agents);

Example3.4.8

select cid,cname from customers

where discnt =some(select discnt from customers where city='Dallas' or city='

Boston');

Example3.4.9

select cid from customers

where discnt

Example3.4.10

select distinct c.cname from customers c,orders x where c.cid =x.cid and x.aid='a05';

Example3.5.1

select city from customers

union select city from agents;

Example3.5.2

select c.cid from customers c where not exxists(select * from agents a where a.city='New York' and

not exists (select * from orders x where x.cid=c.cid and x.aid=a.aid));

3. 验证、分析作业题: 3.1 (2.5 (a), (c), (e), (g),(k))( (o), (s)); 3.2

2.5（a)Find all(cid,aid,pid)triples for customer,agent,product combinations that are all in the same city.Nothing about orders is involved in this selectio. select c.cid,a.aid,p.pid from customers c,agents a,products p where c.city=a.city and a.city=p.city

(c)Find all(cid,aid,pid)triples for customer,agents,product combinations,no two of which are i the same city.

select c.cid,a.aid,p.pid from customers c,agents a,products p where c.city<>a.city and a.city<>p.city and p.city<>c.city

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