mysql设置某字段不能重复

alter table novel.novelsort add unique(name);

select a.id,a.ip,a.creationTime from myTable a right join (
select max(id) id from myTable group by ip) b on b.id = a.id
where a.id is not null

select a.* from myTable a right join (
select max(id) id from myTable group by ip) b on b.id = a.id
where a.id is not null