row_number() over

Row_number() over只是用于把查询的数据，为他增加一列连续的ID数
如：select *,Row_number() over(order by endtime desc) as IDRank from tb_12530_ring
那么，为表“tb_12530_ring” 增加一列IDRank连续数
select * from (select *,Row_number() over(order by endtime desc) as IDRank from tb_12530_ring 
where id>10000 and id<20000 ) as IDWithRowNumber where IDRank>=1and IDRank<=10
红色字：endtime 是排序，where id>10000 and id<20000 用于条件查询
蓝色字：IDRank>=1and IDRank<=10 是选择1~10的行数
             （因为IDRank列是由Row_number() over生成的连续id数）|

转载:http://www.cnblogs.com/sylfjjp/archive/2010/07/16/1778974.html