Oracle 数据库基础学习 (七) SQL语句综合练习

一、多表查询综合练习

1、 列出高于在30部门工作的所有人员的薪金的员工的姓名、部门名称、部门编号、部门人数

分析:

需要的员工信息：

|-emp表：姓名、部门编号

|-dept表：部门名称、部门编号

|-emp表：统计部门人数

确认关联关系：

　　emp.deptno=dept.deptno

1) 查询出在30部门工作的所有人员的薪金

select sal from emp where deptno=30 ;

2) 找出工资大于30部门的员工的姓名、部门编号（返回多行单列数据，在where子句子查询）

select e.ename, e.deptno, e.sal
from emp e
where e.sal >all (select sal from emp where deptno=30) ;

3) 统计显示部门的名称

select e.deptno, e.sal, d.dname
from emp e, dept d
where sal >all (select sal from emp where deptno=30) and (d.deptno = e.deptno) ;

4) 在emp表中统计出部门的各个人数，子查询中查询部门人数，返回多行多列表

select deptno dno, count(empno)  count
from emp
group by deptno ;

5) 多行多列表在from子句中查询结果

select e.ename,d.dname, e.deptno, temp.count
from emp e, dept d,(select deptno dno, count(empno) count
from emp
group by deptno) temp
where sal >all (select sal from emp where deptno=30)
and (d.deptno = e.deptno)
and temp.dno=d.deptno ;

2、 列出与scott从事相同工作的所有员工信息以及部门名称，部门人数，领导姓名

分析：

需要的员工信息：

|-emp表：员工名称，工资

|-dept表：部门名称

|-emp表：统计部门人数

|-emp表：统计领导信息

确认关联关系：

|-部门联系 emp.deptno=dept.deptno

|-领导联系 emp.mgr=memp.empno

1) 查询出scott从事的工作

select job from emp where ename='SCOTT';

2) 与scott从事相同工作的所有员工信息，子查询返回“单行单列“

select e.empno, e.ename, e.sal
from emp e
where e.job=(select job from emp where ename='SCOTT');

3) 加入显示部门名称，加入dept表

select e.empno, e.ename, e.sal, d.dname
from emp e, dept d
where e.job=(select job from emp where ename='SCOTT')
and (d.deptno = e.deptno);

4) 加入显示部门人数，子查询返回多行多列

select  e.empno, e.ename, e.sal, d.dname , temp.cou
from emp e, dept d, (select deptno dno, count(empno) cou
from emp
group by deptno) temp
where job=(select job from emp where ename='SCOTT')
and (d.deptno = e.deptno)
and temp.dno=d.deptno;

5) 加入显示领导姓名，使用emp表的自身关联，并消除“SCOTT”

select e.empno, e.ename, e.job, e.mgr, e.hiredate, e.sal, e.comm, d.dname, temp.cou, m.ename
from emp e, dept d, (select deptno dno, count(empno) cou
from emp
group by deptno) temp, emp m
where e.job=(select job
from emp
where ename='SCOTT')
and d.deptno = e.deptno
and temp.dno=d.deptno
and e.mgr=m.empno
and e.ename<>'SCOTT';

3、查询出比 'SMITH'或'ALLEN'薪资高的员工的编号、姓名、工资、部门名称、领导名称、部门人数、平均工资和最高及最低工资

select e.empno, e.ename, e.sal, d.dname, m.ename, temp.count, temp.avg, temp.max, temp.min
from emp e,dept d,emp m,(select deptno dno, count(empno) count, avg(sal) avg , max(sal) max, min(sal) min
from emp
group by deptno) temp
where e.sal >any (select sal from emp where ename in ('SMITH','ALLEN'))
--and e.ename<>'SMITH'
--and e.ename<>'ALLEN'
and e.ename not in ('SMITH','ALLEN')
and e.deptno=d.deptno(+)
and e.mgr=m.empno(+)
and d.deptno=temp.dno(+);

4、查询出有比直接领导就职时间早的雇员的编号，姓名，部门名称，部门位置和部门人数

select e.empno, e.ename, d.dname, d.loc, temp.count
from emp e, emp m, dept d, (select deptno dno, count(empno) count
from emp
group by deptno) temp
where e.mgr=m.empno(+)
and e.hiredate < m.hiredate
and d.deptno=e.deptno(+)
and d.deptno=temp.dno(+);

5、列出所有“CLERK”(办事员 )的姓名，部门名称，部门人数和工资等级

select e.ename, d.dname, temp.count, s.grade
from emp e,
dept d,
(select deptno dno, count(empno) count from emp group by deptno) temp,
salgrade s
where e.job = 'CLERK'
and d.deptno = e.deptno
and d.deptno = temp.dno
and e.sal between s.losal and s.hisal;

二、创建一个超市商品记录数据库，并进行增加，修改，删除，查询等操作，设置约束条件，包括主外键，非空约束等

1、 数据表的建立

--数据删除
DROP TABLE purchase PURGE;
DROP TABLE product PURGE;
DROP TABLE customer PURGE;

--数据表的建立
--1、创建顾客表：
create table customer (
customerid   varchar2(3),
c_name       varchar2(20) not null,
loction      varchar2(30),
CONSTRAINT pk_customerid PRIMARY KEY(customerid)  --主键设置
);

--2、创建商品表：
create table product(
productid    varchar2(3),
productname  varchar2(20) not null,
unitprice    number,
p_category   varchar2(20),
provider     varchar2(20),
CONSTRAINT ck_unitprice CHECK (unitprice>0),    --检查设置
CONSTRAINT pk_productid PRIMARY KEY(productid)  --主键设置
);

--3、创建购买表：
create table purchase(
customerid  varchar2(3),
productid   varchar2(20),
quantity    number,
CONSTRAINT ck_quantity CHECK (quantity BETWEEN 0 AND 20),  --检查设置
CONSTRAINT fk_customerid FOREIGN KEY(customerid) REFERENCES  customer(customerid) ON DELETE CASCADE, --外键的设置
CONSTRAINT fk_productid  FOREIGN KEY(productid) REFERENCES  product(productid) ON DELETE CASCADE     --外键的设置

);

--提交事务
commit;

2、 数据的添加

--测试数据
INSERT INTO product(productid, productname, unitprice, p_category, provider)
VALUES('M01', '佳洁士', 8.00, '牙膏','宝洁');
INSERT INTO product(productid, productname, unitprice, p_category, provider)
VALUES('M02', '高露洁', 6.50 , '牙膏','高露洁');
INSERT INTO product(productid, productname, unitprice, p_category, provider)
VALUES('M03', '洁诺', 5.00, '牙膏','联合利华');
INSERT INTO product(productid, productname, unitprice, p_category, provider)
VALUES('M04', '舒肤佳', 3.00, '香皂','宝洁');
INSERT INTO product(productid, productname, unitprice, p_category, provider)
VALUES('M05', '夏士莲', 5.00, '香皂','联合利华');
INSERT INTO product(productid, productname, unitprice, p_category, provider)
VALUES('M06', '雕牌', 2.50, '洗衣粉','纳爱斯');
INSERT INTO product(productid, productname, unitprice, p_category, provider)
VALUES('M07', '中华', 3.50, '牙膏','联合利华');
INSERT INTO product(productid, productname, unitprice, p_category, provider)
VALUES('M08', '汰渍', 3.00, '洗衣粉','宝洁');
INSERT INTO product(productid, productname, unitprice, p_category, provider)
VALUES('M09', '碧浪', 4.00, '洗衣粉','宝洁');

INSERT INTO customer(customerid, c_name, loction)
VALUES('C01', 'Dennis', '海淀');
INSERT INTO customer(customerid, c_name, loction)
VALUES('C02', 'John', '朝阳');
INSERT INTO customer(customerid, c_name, loction)
VALUES('C03', 'Tom', '东城');
INSERT INTO customer(customerid, c_name, loction)
VALUES('C04', 'Jenny', '东城');
INSERT INTO customer(customerid, c_name, loction)
VALUES('C05', 'Rick', '西城');

INSERT INTO purchase(customerid, productid, quantity)
VALUES('C01', 'M01', 3);
INSERT INTO purchase(customerid, productid, quantity)
VALUES('C01', 'M05', 2);
INSERT INTO purchase(customerid, productid, quantity)
VALUES('C01', 'M08', 2);
INSERT INTO purchase(customerid, productid, quantity)
VALUES('C02', 'M02', 5);
INSERT INTO purchase(customerid, productid, quantity)
VALUES('C02', 'M06', 4);
INSERT INTO purchase(customerid, productid, quantity)
VALUES('C03', 'M01', 1);
INSERT INTO purchase(customerid, productid, quantity)
VALUES('C03', 'M05', 1);
INSERT INTO purchase(customerid, productid, quantity)
VALUES('C03', 'M06', 3);
INSERT INTO purchase(customerid, productid, quantity)
VALUES('C03',  'M08',1 );
INSERT INTO purchase(customerid, productid, quantity)
VALUES('C04', 'M03', 7);
INSERT INTO purchase(customerid, productid, quantity)
VALUES('C04', 'M04', 3);
INSERT INTO purchase(customerid, productid, quantity)
VALUES('C05', 'M06', 2);
INSERT INTO purchase(customerid, productid, quantity)
VALUES('C05', 'M07', 8);

--提交事务
commit;

3、对数据库进行操作

第一问：查询出购买过宝洁产品的用户详细信息

select  DISTINCT *
from customer
where customerid in (
select customerid
from  purchase
where productid in (
select productid
from product
where provider='宝洁'
));

第二问：查询出购买了顾客"Dennis"购买过的所有商品的顾客信息

1) 查询出顾客"Dennis"所购买的商品

select productid
from purchase
where customerid in (
select customerid
from customer
where c_name = 'Dennis');

2) 使用exists()判断行，MINUS集合运算比较出其他顾客与“Dennis”所购买商品的集合，集合为空表示购买过“Dennis”所购买所有商品，集合不为空则没有购买过“Dennis”所购买所有商品。

select *
from customer cu2
where  not exists ((
select p1.productid
from purchase p1
where p1.customerid in (
select customerid
from customer
where c_name = 'Dennis'))
MINUS
(select p2.productid
from purchase p2
where p2.customerid in (
select cu1.customerid
from customer cu1
　　　　　　　　　　　　　　　　　　　　　where cu1.c_name=cu2.c_name)))
and c_name<>'Dennis';

补充：

a、eixsts()的相关用法：http://www.cnblogs.com/netserver/archive/2008/12/25/1362615.html

b、集合运算union、union all、intersect和minus

①union:连接两个子查询的和，消除重复行

②union all: 连接两个子查询的和，不消除重复行

③intersect：获取两个子查询的结果，值返回同时存在两个子查询的数据行

④minus：返回从第一个子查询的结果，但没有在第二个子查询返回的结果

第三问：查询出牙膏销量最高的供应商

1) 查询出供应牙膏的供应商和商品id

select  provider,productid
from product
where p_category='牙膏' ;

2) 查询出牙膏销量最高的供应商

select temp.provider, sum(p.quantity) sum
from purchase p, (select  provider,productid
from product
where p_category='牙膏') temp
where p.productid=temp.productid
group by temp.provider
HAVING sum(p.quantity)=(
select max(sum(p.quantity))
from purchase p, (select  provider,productid
from product
where p_category='牙膏') temp
where p.productid=temp.productid
group by temp.provider);

第四问：所有的牙膏商品单价增加10%

UPDATE product SET unitprice=unitprice*1.1 where p_category='牙膏' ;

第五问：删除从未被购买的商品

DELETE FROM product WHERE productid not in (select productid from purchase);