create table pm_stu
(stu_id varchar2(20) primary key,
stu_name varchar2(20));
insert into pm_stu values('1','张三');
insert into pm_stu values('2','李四');
insert into pm_stu values('3','王五');
insert into pm_stu values('4','赵六');
(stu_id varchar2(20) primary key,
stu_name varchar2(20));
insert into pm_stu values('1','张三');
insert into pm_stu values('2','李四');
insert into pm_stu values('3','王五');
insert into pm_stu values('4','赵六');