查重：
select * from 表名 where 重复记录的字段名称 in ( select 重复记录字段的名称 from 表名 group by 重复记录的字段名称 having count(重复记录的字段名称)>1)
如有需要可加另加条件，列如：在user表中找出name = 张三且status=0
select * from ‘user’ where name in ( select name from ‘user’ group by name having count(name)>1) and status =0;