幽灵资源网 Design By www.bzswh.com
有一个表user，字段分别有id、nick_name、password、email、phone。
一、单字段（nick_name）
查出所有有重复记录的所有记录
select * from user where nick_name in (select nick_name from user group by nick_name having count(nick_name)>1);
查出有重复记录的各个记录组中id最大的记录
select * from user where id in (select max(id) from user group by nick_name having count(nick_name)>1);
查出多余的记录，不查出id最小的记录
select * from user where nick_name in (select nick_name from user group by nick_name having count(nick_name)>1) and id not in (select min(id) from user group by nick_name having count(nick_name)>1);
删除多余的重复记录，只保留id最小的记录
delete from user where nick_name in (select nick_name from (select nick_name from user group by nick_name having count(nick_name)>1) as tmp1) and id not in (select id from (select min(id) from user group by nick_name having count(nick_name)>1) as tmp2);
二、多字段（nick_name,password）
查出所有有重复记录的记录
select * from user where (nick_name,password) in (select nick_name,password from user group by nick_name,password where having count(nick_name)>1);
查出有重复记录的各个记录组中id最大的记录
select * from user where id in (select max(id) from user group by nick_name,password where having count(nick_name)>1);
查出各个重复记录组中多余的记录数据，不查出id最小的一条
select * from user where (nick_name,password) in (select nick_name,password from user group by nick_name,password having count(nick_name)>1) and id not in (select min(id) from user group by nick_name,password having count(nick_name)>1);
删除多余的重复记录，只保留id最小的记录
delete from user where (nick_name,password) in (select nick_name,password from (select nick_name,password from user group by nick_name,password having count(nick_name)>1) as tmp1) and id not in (select id from (select min(id) id from user group by nick_name,password having count(nick_name)>1) as tmp2);
以上就是MySQL 数据查重、去重的实现语句的详细内容，更多关于MySQL 数据查重、去重的资料请关注其它相关文章！
幽灵资源网 Design By www.bzswh.com
广告合作：本站广告合作请联系QQ：858582 申请时备注：广告合作（否则不回）
免责声明：本站文章均来自网站采集或用户投稿，网站不提供任何软件下载或自行开发的软件！ 如有用户或公司发现本站内容信息存在侵权行为，请邮件告知！ 858582#qq.com
免责声明：本站文章均来自网站采集或用户投稿，网站不提供任何软件下载或自行开发的软件！ 如有用户或公司发现本站内容信息存在侵权行为，请邮件告知！ 858582#qq.com
幽灵资源网 Design By www.bzswh.com
暂无评论...