Question

对令人困惑的问题标题道歉，但我不确定如何描述手头的问题。

我在Oracle 9i中有两个表：

Pricing
-------
SKU
ApplicableTime
CostPerUnit

Inventory
---------
SKU
LastUpdatedTime
NumberOfUnits

Pricing包含在特定Unix时间对每个特定SKU项目的成本的增量更新。例如，如果我有记录：

SKU    ApplicableTime    CostPerUnit
------------------------------------
12345  1000              1.00
12345  1500              1.50

，然后项目12345在1000到1500之间的任何时间内每单位1.00美元，在1500之后的任何时间都是1.50美元。

Inventory包含SKU，上次更新时间和单位数。

我尝试做的是构建一个查询，以便对Inventory中的每一行，基于SKU加入两个表，我找到Pricing.ApplicableTime的最大值。不大于Inventory.LastUpdatedTime，从CostPerUnit获取该特定记录的Pricing，并计算TotalCost = CostPerUnit * NumberOfUnits：

SKU    TotalCost
-----------------------------------------------------------------------------------
12345  (CostPerUnit at most recent ApplicableTime <= LastUpdatedTime)*NumberOfUnits
12346  <same>
...    ...

我该怎么做？

Answer 1

SELECT * 
FROM
  (select  p.SKU,
  p.ApplicableTime,
  p.CostPerUnit*i.NumberOfUnits as cost,
  row_number over (partition by p.SKU order by p.ApplicableTime desc) as rnk
  from Pricing p
  join  
  Inventory i on (p.sku = i.sku and i.LastUpdatedTime > p.ApplicableTime)
  )
where rnk=1

Answer 2

select SKU, i1.NumberOfUnits * p1.CostPerUnit as TotalCost
from Inventory i1, 
join (
    select SKU, max(ApplicableTime) as ApplicableTime, max(i.LastUpdatedTime) as LastUpdatedTime
    from Pricing p
    join Inventory i on p.sku = i.sku
    where p.ApplicableTime < i.LastUpdatedTime
    group by SKU
) t  on i1.sku = t.sku and i1.LastUpdatedTime = t.LastUpdatedTime
join Pricing p1 on p1.sku = t.sku and p1.ApplicableTime = t.ApplicableTime

如何连接两个表，其最大值不大于列的另一个值

2 个答案: