https://www.jinchutou.com/p-32807931.html


安装redhat8
https://www.kclouder.cn/rhel8-beta-experience/


select e.empno,e.ename,m.empno,m.ename from emp e,emp m where e.mgr=m.empno(+);? 


像表中插入数据
 insert into product values('M01','佳洁士','8.00','牙膏','宝洁');
 insert into product values('M02','gaorujie','6.50','yagao','gaorujie');
 insert into product values('M03','jienuo','5.00','yagao','lianhelibi');
 insert into product values('M04','shufujia','3.00','xiangzao','baojie');
 insert into product values('M05','xiashilian','5.00','xiangzao','lianhelihua');
 insert into product values('M06','diaopai','2.50','xiyifeng','naaisi');
 inert into product values('M07','zhonghua','3.50','yagao','lianhebihua');
 insert into product values('M08','taizhi','3.00','xiyifeng','baojie');
 insert into product values('M09','bilang','4.00','xiyifeng','baojie');
像customer插入数据
insert into customer values('c02','Dennis','zhaoyang');
insert into customer values('c01','John','haiding');
insert into customer values('c03','Tom','dongcheng');
insert into customer values('c04','Jenny','dongcheng');
insert into customer values('c05','Rick','xicheng');

像purcase插入数据
insert into purcase values('c02','M05','2');
insert into purcase values('c03','M08','2');
insert into purcase values('c04','M02','5');
insert into purcase values('c05','M06','4');
insert into purcase values('c06','M01','1');
insert into purcase values('c07','M05','1');

insert into purcase values('c08','M06','3');
insert into purcase values('c09','M08','1');
insert into purcase values('c10','M03','7');

insert into purcase values('c11','M04','3');
insert into purcase values('c12','M06','2');
insert into purcase values('c13','M07','8');


select c.customerid,c.customername from product p,customer c,purcase p where p.id=p.customerid and c.customerid=p.customerid and provider='baojie';