窗口分析函数 sum() over() :可以实现在窗口中进行逐行累加
测试数据:
这个是网上比较经典的案例了
2: jdbc:hive2://hadoop-03:10000> select * from t_access_amount;
+----------------------+------------------------+-------------------------+--+
| t_access_amount.uid | t_access_amount.month | t_access_amount.amount |
+----------------------+------------------------+-------------------------+--+
| A | 2015-01 | 33 |
| A | 2015-02 | 10 |
| A | 2015-03 | 20 |
| B | 2015-01 | 30 |
| B | 2015-02 | 15 |
| B | 2015-03 | 45 |
| C | 2015-01 | 30 |
| C | 2015-02 | 40 |
| C | 2015-03 | 30 |
+----------------------+------------------------+-------------------------+--+
要求:求出每个人截止到每个月的总额
即要得到如下表格
+------+----------+---------+-------------+--+
| uid | month | amount | accumulate |
+------+----------+---------+-------------+--+
| A | 2015-01 | 33 | 33 |
| A | 2015-02 | 10 | 43 |
| A | 2015-03 | 20 | 63 |
| B | 2015-01 | 30 | 30 |
| B | 2015-02 | 15 | 45 |
| B | 2015-03 | 45 | 90 |
| C | 2015-01 | 30 | 30 |
| C | 2015-02 | 40 | 70 |
| C | 2015-03 | 30 | 100 |
+------+----------+---------+-------------+--+
hql 语句
select uid,month,amount,
sum(amount) over(partition by uid order by month rows between unbounded preceding and current row) as accumulate
from t_access_amount;
来源：CSDN
作者：nancy小心心
链接：https://blog.csdn.net/weixin_43548518/article/details/104117054