ORACLE分页SQL语句

1.根据ROWID来分select * from t_xiaoxi where rowid in(select rid from (select rownum rn,rid from(select rowid rid,cid fromt_xiaoxi order by cid desc) where rownum<10000 where="" rn="">9980) order by cid desc;执行时间0.03秒2.按分析函数来分select * from (select t.*,row_number() over(order by cid desc) rk from t_xiaoxi t) where rk<10000 and="" rk="">9980;执行时间1.01秒3.按ROWNUM来分select * from(select t.*,rownum rn from(select * from t_xiaoxi order by cid desc) t where rownum<10000 where="" rn="">9980;执行时间0.1秒其中t_xiaoxi为表名称，cid为表的关键字段，取按CID降序排序后的第9981-9999条记录，t_xiaoxi表有70000多条记录个人感觉1的效率最好，3次之，2最差

就第三条理解