ORACLE分页查询SQL语法——最高效的分页
--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 emp t
WHERE hire_date BETWEEN TO_DATE ('20060501', 'yyyymmdd')
AND TO_DATE ('20060731', 'yyyymmdd')
AND ROWNUM = 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 emp t
WHERE hire_date BETWEEN TO_DATE ('20060501', 'yyyymmdd')
AND TO_DATE ('20060731', 'yyyymmdd')
ORDER BY create_time DESC, emp_no) tt
WHERE ROWNUM = 10;
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=======================垃圾但又似乎很常用的分页写法==========================
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--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 = 10;
--TABLE_ALIAS.ROWNObetween 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 = 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 = 10;
yangtingkun分析：
--- from ：http://yangtingkun.itpub.net/post/468/100278
Oracle的分页查询语句基本上可以按照本文给出的格式来进行套用。
分页查询格式：
SELECT *
FROM (SELECT a.*, ROWNUM rn
FROM (SELECT *
FROM table_name) a
WHERE ROWNUM = 21
其中最内层的查询SELECT * FROM TABLE_NAME表示不进行翻页的原始查询语句。ROWNUM = 21控制分页查询的每页的范围。
上面给出的这个分页查询语句，在大多数情况拥有较高的效率。分页的目的就是控制输出结果集大小，将结果尽快的返回。在上面的分页查询语句中，这种考虑主要体现在WHERE ROWNUM
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