1. 問題描述

有時load或者insert操作導致 表數據有重復

2. 解決方案

通過臨時表、主鍵id、倒騰去重

示例

2.1 create table student(

　　name varchar(30) not null default ‘‘,

age smallint(3) not null default 0,

　　love varchar(50) not null default ‘‘

)

插入一些數據......(包含重復)

insert into student(name,age,love) values(‘zhangsan‘,15,‘basketball‘);

insert into student(name,age,love) values(‘zhangsan‘,15,‘basketball‘);

insert into student(name,age,love) values(‘zhangsan‘,15,‘basketball‘);

2.2 備份(全部數據或部分數據)

create table student_backup like student;

insert into student_backup select * from student where name=‘zhangsan‘;

2.3 創建臨時表一
create table student_tmp like student;

insert into student_tmp select * from student where name=‘zhangsan‘;

alter table student_tmp add id int primary key auto_increment not null ;

2.4 創建臨時表二

create table tmp2 (

id int auto_increment not null,

primary key(id)

);

insert into tmp2 select min(id) as id from student_tmp group by name,age,love;

2.5 創建臨時表三

create table tmp3 like student_tmp;

insert into tmp3 select student_tmp.* from student_tmp,tmp2 where student_tmp.id=tmp2.id;

alter table tmp3 drop column id;

2.6 刪除重復數據

delete from student where name=‘zhangsan‘;

2.7 插入去重後數據

insert into student select * from tmp3;

Done!

mysql 去除重復數據