Hive分析函数的使用

测试数据集：

SQL语句## COUNT、SUM、MIN、MAX、AVG

## COUNT、SUM、MIN、MAX、AVG

select user_id

,user_type

,sales

,sum(sales) OVER(partition by user_type order by sales asc) as sales_1 --默认为从起点到当前行

,sum(sales) OVER(partition by user_type order by sales asc ROWS between UNBOUNDED PRECEDING and current row) as sales_2 --从起点到当前行，结果与sales_1不同。

,sum(sales) OVER(partition by user_type order by sales asc ROWS between 3 PRECEDING and current row) as sales_3 --当前行+往前3行

,sum(sales) OVER(partition by user_type order by sales asc ROWS between 3 PRECEDING and 1 FOLLOWING) as sales_4 --当前行+往前3行+往后1行

,sum(sales) OVER(partition by user_type order by sales asc ROWS between current row and UNBOUNDED FOLLOWING) as sales_5 --当前行+往后所有行

,sum(sales) OVER(partition by user_type) as sales_6 --分组内所有行

from order_detail

order by user_type

,sales

,user_id;

SQL代码

运行结果

注意:

结果和ORDER BY相关,默认为升序

如果不指定ROWS BETWEEN,默认为从起点到当前行;

如果不指定ORDER BY，则将分组内所有值累加;

关键是理解ROWS BETWEEN含义,也叫做WINDOW子句：

PRECEDING：往前

FOLLOWING：往后

CURRENT ROW：当前行

UNBOUNDED：无界限（起点或终点）

UNBOUNDED PRECEDING：表示从前面的起点

UNBOUNDED FOLLOWING：表示到后面的终点

其他COUNT、AVG，MIN，MAX，和SUM用法一样。