oracle 分页语句

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<span style="font-size:18px;">一、</span>

<span style="font-size:18px;"></span>

<span style="font-size:18px;">select *  from (select a.*, rownum r</span>

<span style="font-size:18px;">          from (select * FROM dept_apply_info o ) a         where rownum <= 4) b where r >= 1;</span>

<span style="font-size:18px;"></span>

<span style="font-size:18px;"></span>

<span style="font-size:18px;"> ---2、分页</span>

<span style="font-size:18px;"> select a.*, rownum r  from (select * from dept_apply_info o ) a where rownum <= 4   and rownum >= 1;</span>

下面转载的是关于各个分页语句效率的比较：

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

原文出处：http://www.cnblogs.com/hxw/archive/2005/09/11/234619.html

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