如何获取配置单元中每个月的最后一个季度和最后半年的平均余额？

Question

我有一个列cust_id, year_, month_, monthly_txn, monthly_bal的表。 我需要计算每个月的前三个月和前六个月的avg(monthly_txn)和variance(monthly_bal) 。 我有一个查询，仅返回上个月而不是每个月的最后三个月和六个月的平均值和方差。 我在Hive中的分析功能不佳。

  SELECT cust_id, avg(monthly_txn)y,variance(monthly_bal)x, FROM ( 
  SELECT cust_id, monthly_txn,monthly_bal,
            row_number() over (partition by cust_id order by year_,month_ desc) r
        from mytable) b WHERE r <= 3 GROUP BY cust_id

但是我想要下面的东西。

输入：

 cust_id     year_   month_     monthly_txn  monthly_bal
1            2018     1              456    8979289
1            2018     2              675    4567
1            2018     3              645    4890
1            2017     1              342    44522
1            2017     2              378    9898900
1            2017     2              456    234492358
1            2017     4              3535   789
1            2017     5              456    345
1            2017     6              598    334

预期的输出：

假设对于txn，季度和半年度txn对于方差也是如此

cust_id     year_    month_     monthly_txn  monthly_bal     q_avg_txn            h_avg_txn
   1         2018      1          456          8979289       avg(456,598,4561)    avg(456,598,4561,3535,4536,378)
   1         2018      2          675          4567          avg(675,456,598)     avg(675,456,3535,4561,598,4536)
   1         2018      3          645          4890          avg(645,675,645)     avg(645,675,645,3535,4561,598)
   1         2017      1          342          44522         avg(342)             avg(342)
   1         2017      2          378          9898900       avg(378,342)         avg(378,342)
   1         2017      3          4536         234492358     avg(4536,372,342)    avg(4536,378,342)
   1         2017      4          3535         789           avg(3535,4536,378)   avg(3535,4536,378,342) 
   1         2017      5          4561         345           avg(4561,3535,4536)  avg(4561,3535,4536,342,378)
   1         2017      6          598          334           avg(598,4561,3535)   avg(598,4561,3535,4536,342,378) 

Answer 1

使用unbounded preceding分析函数（/ *获取季度和半年值），然后使用子查询获取结果。

在Teradata中使用ROWS UNBOUNDED PRECEDING是什么？

Answer 2

如果您有感兴趣的每个月的数据（即没有差距），那么这应该起作用：

select t.*,
       avg(monthly_bal) over (partition by cust_id
                              order by year_, month_ 
                              rows between 2 preceding and current row
                             ) as avg_3,
       avg(monthly_bal) over (partition by cust_id
                              order by year_, month_ 
                              rows between 5 preceding and current row
                             ) as avg_6,
       variance(monthly_bal) over (partition by cust_id
                                   order by year_, month_ 
                                   rows between 2 preceding and current row
                                  ) as variance_3,
       variance(monthly_bal) over (partition by cust_id
                                   order by year_, month_ 
                                   rows between 5 preceding and current row
                                  ) as variance_6
from mytable t;