oracle查询、删除表中相同的数据

delete FROM tablename a 　　WHERE rowid > ( SELECT min(rowid) 　　FROM tablename b 　　WHERE b.id = a.id and b.name=a.name);

select *　 FROM tablename a 　　WHERE rowid > ( SELECT min(rowid) 　　FROM tablename b 　　WHERE b.id = a.id and b.name=a.name);