纠正别人博客中的hive问题

因为有业务需求，所以查看了几篇别人的博客，发现有错误的地方：

1.http://www.cnblogs.com/mobiwangyue/p/8328758.html

2.https://www.jianshu.com/p/51599bab0c00

为了验证业务需求的做法，特地模拟了一些假的数据做相关demo，数据如下：

1.	hive
2.	show databases;
3.	use kukatest2;
4.	show tables;
5.	CREATE TABLE pv_web(order_time date, province string, city string,channel string,order_count string,order_amount string) row format delimited fields terminated by ',' ;
6.	Load data local inpath ‘/carson/order.csv’overwrite into table order.

                     

with temp1 as (select province,city,channel,order_amount from t1),
temp2 as (
	select province,city,channel,sum(order_amount) as num, row_number() over (partition by province,city order by sum(order_amount) desc) rank
	from temp1
	-- where province,city 限制条件
	group by province,city,channel
)
select * from temp2 a where a.rank <= 2




-- 方式一
select class, max(grade) from score group by class;
-- 方式二
select class, grade from 
	(select *, row_number() over 
		(partition by class order by grade desc) grade_desc
	) from score score_sorted)
where grade_desc=1;
-- 方式三
select name, class, grade from 
	(select *, row_number() over 
		(partition by class order by grade desc) grade_desc
	) from score score_sorted)
where grade_desc=1;

 其他相关博客：https://blog.csdn.net/dapanbest/article/details/87800141

                            https://blog.csdn.net/qq_25221835/article/details/82762416（重点推荐看这版本）

                            https://www.cnblogs.com/jifengblog/p/9286800.html  hive的其他函数