Oracle中排序后查询20~40数据

第一种方法： select * from (select t.*,rownum tt from (select * from sup_doc_feedback order by web_doc_id)t where rownum <41) r where r.tt>20

第二中方法：select * from (select * from (select * from sup_doc_feedback t order by web_doc_id )  where rownum <41   minus
                                                  select * from (select * from sup_doc_feedback t order by web_doc_id )  where rownum< 21) order by web_doc_id