sql 以类别分类，查询出前几名的信息

 select * from (select 字段, row_number() over(partition by 字段 order by 字段desc) as _rowCount from 表名) as temp
where _rowCount<3  前3名

select * from (select store, row_number() over(partition by store order by OrigCount desc) as _rowCount from orders) as temp
where _rowCount<3