问题：
有一张Hive表tb_order, 其中(order_id 订单ID, city 城市名称, dt日期分区例如2020-05-01)三个可用字段。
然后我们要统计一下近31天的Top10地区的订单。
共返回 31 * 10调数据，大致思路如下：
select dt, city from (select city, count(order_id) as order_nums from tb_order where dt >= "2020-05-01" and dt < "2020-06-01" group by city order by order_nums desc limit 10
) as t1 group by dt