Oracle分页总汇

Oracle分页总汇
 
select * from
(select a.*,rownum row_num from
(select * from mytable t order by t.id desc) a
where rownum<=10
) b where b.row_num >= 1 order by u_age desc;    
 
select * from 
 
(select a.*,rownum row_num from 
 
(select * from mytable t order by t.id desc) a
 
) b where b.row_num between 1 and 10 
 
.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 from 
 
t_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
 
--1:无ORDER BY排序的写法。(效率最高) 
--(经过测试，此方法成本最低，只嵌套一层，速度最快！即使查询的数据量再大，也几乎不受影响，速度依然！) 
 
SELECT * 
  FROM (Select ROWNUM AS ROWNO, T.* 
           from k_task T 
          where Flight_date between to_date(‘20060501‘, ‘yyyymmdd‘) and 
                to_date(‘20060731‘, ‘yyyymmdd‘) 
            AND ROWNUM <= 20) TABLE_ALIAS 
WHERE TABLE_ALIAS.ROWNO >= 10; 
 
--2:有ORDER BY排序的写法。(效率最高) 
--(经过测试，此方法随着查询范围的扩大，速度也会越来越慢哦！) 
 
SELECT * 
  FROM (SELECT TT.*, ROWNUM AS ROWNO 
           FROM (Select t.* 
                    from k_task T 
                   where flight_date between to_date(‘20060501‘, ‘yyyymmdd‘) and 
                         to_date(‘20060531‘, ‘yyyymmdd‘) 
                   ORDER BY FACT_UP_TIME, flight_no) TT 
          WHERE ROWNUM <= 20) TABLE_ALIAS 
where TABLE_ALIAS.rowno >= 10;
 
--3:无ORDER BY排序的写法。(建议使用方法1代替) 
--(此方法随着查询数据量的扩张，速度会越来越慢哦！) 
--4:有ORDER BY排序的写法.(建议使用方法2代替)
 
SELECT * 
  FROM (Select ROWNUM AS ROWNO, T.* 
           from k_task T 
          where Flight_date between to_date(‘20060501‘, ‘yyyymmdd‘) and 
                to_date(‘20060731‘, ‘yyyymmdd‘)) TABLE_ALIAS 
WHERE TABLE_ALIAS.ROWNO <= 20 
   AND TABLE_ALIAS.ROWNO >= 10; 
--TABLE_ALIAS.ROWNO  between 10 and 100; 
 
--(此方法随着查询范围的扩大，速度会越来越慢哦！) 
 
SELECT * 
  FROM (SELECT TT.*, ROWNUM AS ROWNO 
           FROM (Select * 
                    from k_task T 
                   where flight_date between to_date(‘20060501‘, ‘yyyymmdd‘) and 
                         to_date(‘20060531‘, ‘yyyymmdd‘) 
                   ORDER BY FACT_UP_TIME, flight_no) TT) TABLE_ALIAS 
where TABLE_ALIAS.rowno BETWEEN 10 AND 20; 
 
--5另类语法。(有ORDER BY写法） 
--(语法风格与传统的SQL语法不同，不方便阅读与理解，为规范与统一标准，不推荐使用。) 
 
With partdata as( 
  SELECT ROWNUM AS ROWNO, TT.*  FROM (Select * 
                  from k_task T 
                 where flight_date between to_date(‘20060501‘, ‘yyyymmdd‘) and 
                       to_date(‘20060531‘, ‘yyyymmdd‘) 
                 ORDER BY FACT_UP_TIME, flight_no) TT 
   WHERE ROWNUM <= 20) 
    Select * from partdata where rowno >= 10; 
 
--6另类语法 。(无ORDER BY写法） 
 
With partdata as( 
  Select ROWNUM AS ROWNO, T.* 
    From K_task T 
   where Flight_date between to_date(‘20060501‘, ‘yyyymmdd‘) and 
         To_date(‘20060531‘, ‘yyyymmdd‘) 
     AND ROWNUM <= 20) 
    Select * from partdata where Rowno >= 10;