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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 <= 20) table_alias
WHERE table_alias.rowno >= 10;
2.有ORDER BY排序的写法。(效率较高)
(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_n
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