常用的Oracle查詢語句

1.無ORDER BY排序的寫法。(效率最高)

經過測試，此方法成本最低，只嵌套一層，速度最快！即使查詢的數據量再大，也幾乎不受影響，速度依然！

sql語句如下：

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排序的寫法。(效率最高)

經過測試，此方法隨著查詢範圍的擴大，速度也會越來越慢！

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.無ORDER BY排序的寫法。(建議使用方法1代替)
此方法隨著查詢數據量的擴張，速度會越來越慢！

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排序的寫法.(建議使用方法2代替)

此方法隨著查詢範圍的擴大，速度也會越來越慢！

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.另類語法。(有ORDER BY寫法）

該語法風格與傳統的SQL語法不同，不方便閱讀與理解，為規範與統一標準，不推薦使用。此處貼出代碼供大家參考之用。

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.另類語法 。(無ORDER BY寫法）

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;

常用sql 分頁語句(Oracle)