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844天前--1.创建表 |
create table student( |
id number(19) not null, |
name varchar2(20), |
sex number(2), |
primary key(id) |
); |
--2.创建序列 |
create sequence s_student |
increment by 1 start with 1 nomaxvalue nocycle nocache; |
--3.插入若干条数据 |
insert into student values(s_student.nextval, 'student001', 0); |
insert into student values(s_student.nextval, 'student002', 0); |
insert into student values(s_student.nextval, 'student003', 0); |
insert into student values(s_student.nextval, 'student004', 0); |
insert into student values(s_student.nextval, 'student005', 0); |
select * from student; |
--4.复制数据并插入当前表的语句 |
insert into student |
select s_student.nextval, student.name, student.sex from student; |
--删除重复数据 |
delete from student |
where name in (select name from student group by name having count(*) > 1) |
and id not in (select min(id) from student group by name having count(*)>1); |
中级程序员
by: 觉 发表于：2017-09-19 16:15:59 顶(0) | 踩(0) 回复
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