由于Oracle不支持select top 语句，所以在Oracle中经常是用order by 跟rownum的组合来实现select top n的查询。简单地说，实现方法如下所示：select 列名1 ...列名n from(select 列名1 ...列名nfrom 表名 order by 列名1)where rownum <=N(抽出记录数)order by rownum asc如：select id,name from (select id,name from student order by name) where rownum<=10 order by rownum asc按姓名排序取出前十条数据附：取100-150条数据的方法1.最佳选择：利用分析函数row_number() over ( partition by col1 order by col2 )比如想取出100-150条记录,按照tname排序select tname,tabtype from (select tname,tabtype,row_number() over ( order by tname ) rn from tab) where rn between 100 and 150;2. 使用rownum 虚列select tname,tabtype from (select tname,tabtype,rownum rn from tab
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第1个回答 2012-11-13
由于Oracle不支持select top 语句，所以在Oracle中经常是用order by 跟rownum
的组合来实现select top n的查询。
简单地说，实现方法如下所示：
select 列名1 ...列名n from(select 列名1 ...列名n
from 表名 order by 列名1)where rownum <=N(抽出记录数)
order by rownum asc
如：select id,name from (select id,name from student order by name) where rownum<=10 order by rownum asc
按姓名排序取出前十条数据
附：取100-150条数据的方法1.
最佳选择：利用分析函数
row_number() over ( partition by col1 order by col2 )比如想取出100-150条记录,按照tname排序
select tname,tabtype from (
select tname,tabtype,row_number() over ( order by tname ) rn from tab
) where rn between 100 and 150;
2. 使用rownum 虚列
select tname,tabtype from (
select tname,tabtype,rownum rn from tab
的组合来实现select top n的查询。
简单地说，实现方法如下所示：
select 列名1 ...列名n from(select 列名1 ...列名n
from 表名 order by 列名1)where rownum <=N(抽出记录数)
order by rownum asc
如：select id,name from (select id,name from student order by name) where rownum<=10 order by rownum asc
按姓名排序取出前十条数据
附：取100-150条数据的方法1.
最佳选择：利用分析函数
row_number() over ( partition by col1 order by col2 )比如想取出100-150条记录,按照tname排序
select tname,tabtype from (
select tname,tabtype,row_number() over ( order by tname ) rn from tab
) where rn between 100 and 150;
2. 使用rownum 虚列
select tname,tabtype from (
select tname,tabtype,rownum rn from tab
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