Oracle分页
①采用rownum关键字(三层嵌套)
SELECT * FROM(
SELECT A.*,ROWNUM num FROM
(SELECT * FROM t_order)A
WHERE
ROWNUM<=15)
WHERE num>=5;--返回第5-15行数据
②采用row_number解析函数进行分页(效率更高)
SELECT xx.* FROM(
SELECT t.*,row_number() over(ORDERBY o_id)AS num
FROM t_order t
)xx
WHERE num BETWEEN 5AND 15;
--返回第5-15行数据
解析函数能用格式
函数() over(pertion by 字段 order by 字段);
Pertion 按照某个字段分区
Order 按照勒个字段排序
select * from (select t.*,row_number() over (order by id) a from ztemp t)s where
s.a between 0 and 10;
SELECT * FROM (
SELECT t.*,row_number() over(ORDER BY n_count DESC) r
FROM t_news t
ORDER BY t.n_count DESC
) t
WHERE r BETWEEN 4 AND 6
--通用语法： 解析函数() over(partition by 字段 order by 字段)
1.根据ROWID来分<!--more-->
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;
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;
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;
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
1的效率最好，3次之，2最差