mysql删除重复数据只保留一条
delete from toutiao where title in (SELECT a.title from (select title from toutiao group by title having count(title) > 1) a )and id not in (SELECT b.id from (select id from toutiao group by title having count(title) > 1) b )
delete from toutiao where title in (SELECT a.title from (select title from toutiao group by title having count(title) > 1) a )and id not in (SELECT b.id from (select id from toutiao group by title having count(title) > 1) b )