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);