摘要：一：查询1.查询出表中某个字段重复的记录select * from table where ttt in (selectttt from table group by ttt table where count(ttt)>1)2.查询表中字段和另一张表字段值相同的记录select * from table where ttt in (select ttt_1 from table_1 group by ttt_1 where count(ttt_1)>1 )3.查询出无重复记录的结果（例如：两条完全相同的记录，只取一条）select distinct * from table4查询 阅读全文