--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!)
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;
--4:有ORDER BY排序的写法.(建议使用方法2代替)
--(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;