oracle last_value 函数和预测

Question

我需要从我的合同、项目表中返回一个包含最后日期的最后一个值的结果集；稍后我将需要使用此结果集来预测我预测的剩余月份的值。 我似乎一无所获，我需要记录最后一个日期、每个项目和合同的价值对并进行项目。 我只到了第一部分，即提取最后一个日期，值；第二部分也需要帮助，即获取此结果并进行投影。 我们开始：

我的桌子

contrato,projeto,data,valor
C001    P1  01-APR-15   10
C001    P1  01-APR-15   10
C001    P1  01-MAY-15   15
C001    P2  01-MAY-15   19
C001    P2  01-JUN-15   21
C002    P1  01-JUL-15   19
C002    P2  01-AUG-15   19

我的查询

select CONTRATO,PROJETO,FCST,
LAST_VALUE("PERIODO" IGNORE NULLS)OVER (PARTITION BY contrato,projeto,FCST,periodo   ORDER BY contrato,projeto,FCST RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING)LAST_DATE
from(
select CONTRATO,PROJETO,periodo,
  LAST_VALUE("VALOR" IGNORE NULLS)OVER (PARTITION BY contrato,projeto,periodo,valor ORDER BY PERIODO,contrato,projeto RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING )FCST
  FROM "HYP_STAGE"."INVENT_TABLE_FCST"
  )ORDER BY CONTRATO,PROJETO,PERIODO;

我的结果集，是重复几个月的值，每个月只需要一个值；

C001    P1  10  01-APR-15
C001    P1  10  01-APR-15
C001    P1  15  01-MAY-15
C001    P2  19  01-MAY-15
C001    P2  21  01-JUN-15
C002    P1  19  01-JUL-15
C002    P2  19  01-AUG-15

非常感谢！

Answer 1

这是您可能需要的查询：

SQLFiddle demo

select distinct contrato, projeto, 
    last_value(periodo) over (partition by contrato, projeto 
      order by periodo nulls first 
      rows between unbounded preceding and unbounded following) p,
    last_value(valor) over (partition by contrato, projeto 
      order by periodo nulls first 
      rows between unbounded preceding and unbounded following) v
  from INVENT_TABLE_FCST order by contrato, projeto

关于您关于未来期间预测结果的问题的第二部分，您没有解释预测结果的含义。

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如果我有更多的变量，如段、产品，查询将如何？

我怀疑片段和产品应该与 contrato 和 projecto 以相同的方式处理，因此您需要将这些列添加到 select ... 部分和 partition by... 部分中。

但您可能希望像 valor 一样类比对待它们，这取决于您的需求。

第二部分，需要将上个月的值再推算48个月（填写相同的值）

为此，我们需要一些分层查询来生成新时期，这里我使用了recursive CTE：

with data(n, contrato, projeto, periodo, valor) as (
  select distinct 1, contrato, projeto,
      last_value(periodo) over (partition by contrato, projeto
        order by periodo nulls first 
        rows between unbounded preceding and unbounded following) periodo,
      last_value(valor) over (partition by contrato, projeto
        order by periodo nulls first 
        rows between unbounded preceding and unbounded following) valor
    from INVENT_TABLE_FCST  
  union all
  select n+1, contrato, projeto, add_months(periodo, 1), valor
    from data where n<48 )
select contrato, projeto, periodo, valor 
  from data order by contrato, projeto, periodo

完美！效果很好！

那么为什么不将答案标记为已接受？ ;-)

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还有一点：如果您的表中有任何主键，那就太好了，所以我们有不同的、递增的 确保分区和排序正确的值。