mysql rank

问题：取各网站pv top 10记录。

解决：rank

如下：

select site_id,pv_count,rank
from (
select A.site_id,A.pv_count,if(@site=site_id,@curRank := @curRank+1,@curRank := 1) as rank,@site := site_id
from (select site_id,pv_count from report_site_page where date='2013-09-08' order by site_id,pv_count desc) A,(select @curRank := 0,@site := null) B
) C 
where rank <= 10;

关键点：mysql变量，if判断。