第一次查询：查询身份证编号和出现次数
select cardid,count(cardid) as total from p_person_info group by cardid
在第一次查询结果进行二次查询：查询身份证出现次数大于1以上
select cardid from (select cardid,count(cardid) as total from p_person_info group by cardid) temp where temp.total>1
第一次查询：查询身份证编号和出现次数
select cardid,count(cardid) as total from p_person_info group by cardid
在第一次查询结果进行二次查询：查询身份证出现次数大于1以上
select cardid from (select cardid,count(cardid) as total from p_person_info group by cardid) temp where temp.total>1
原文：http://www.cnblogs.com/zsg88/p/8063784.html