如何加入2个表来分配项目？

Question

我创建了2个包含库存信息的表(项目,位置,数量).其中一个NeedInv项目/位置需要X多个项目.另一个HaveInv项目/位置具有过多X的项目.

我正在尝试连接或组合2个表来输出哪些项目应在哪些位置之间传输.我有代码为单个分发位置执行此操作并且我尝试修改它并添加逻辑以使其适用于多个分发位置,但在某些情况下仍然失败.

我创建了一个[sqlfiddle] 1,但示例数据是这样的:

CREATE TABLE NeedInv
    (item int, location varchar(1), need int)

INSERT INTO NeedInv
    (item, location, need)
VALUES
    (100, 'A', 4), (100, 'B', 0), (100, 'C', 2), (200, 'A', 0), (200, 'B', 1), (200, 'C', 1), (300, 'A', 3), (300, 'B', 5), (300, 'C', 0)

CREATE TABLE HaveInv
    (item int, location varchar(1), have int)

INSERT INTO HaveInv
    (item, location, have)
VALUES
    (100, 'A', 0), (100, 'B', 3), (100, 'C', 0), (100, 'D', 3), (200, 'A', 1), (200, 'B', 0), (200, 'C', 0), (200, 'D', 1), (300, 'A', 0), (300, 'B', 0), (300, 'C', 20), (300, 'D', 5)

CREATE TABLE DesiredOutput
    (item int, SourceLocation varchar(1), TargetLocation varchar(1), Qty int)

INSERT INTO DesiredOutput
    (item, SourceLocation, TargetLocation, Qty)
VALUES
    (100, 'B', 'A', 3), (100, 'D', 'A', 1), (100, 'D', 'C', 2), (200, 'A', 'B', 2), (200, 'A', 'C', 3), (200, 'D', 'C', 1), (300, 'C', 'A', 3), (300, 'C', 'B', 3)

我试图通过加入表格来输出这样的东西:

+------+----------------+----------------+-----+
| item | SourceLocation | TargetLocation | Qty |
+------+----------------+----------------+-----+
|  100 | B              | A              |   3 |
|  100 | D              | A              |   1 |
|  100 | D              | C              |   2 |
|  200 | A              | B              |   2 |
|  200 | A              | C              |   3 |
|  200 | D              | C              |   1 |
|  300 | C              | A              |   3 |
|  300 | C              | B              |   3 |
+------+----------------+----------------+-----+

我当前加入2个表的查询如下所示:

select 
    n.*,
    (case when Ord <= Remainder and (RemaingNeed > 0 and RemaingNeed < RemainingInv) then Allocated + RemaingNeed else case when RemaingNeed < 0 then 0 else Allocated end end) as NeedToFill
from (
select
    n.*,
    row_number() over(partition by item order by RN, (case when need > Allocated then 0 else 1 end)) as Ord,
    n.TotalAvail - sum(n.Allocated) over (partition by item) as Remainder
from (
select 
    n.*,
    n.TotalAvail - sum(n.Allocated) over (partition by item order by RN) as RemainingInv,
    n.need - sum(n.Allocated) over (partition by item, location order by RN) as RemaingNeed
from (
  select
    n.*,
    case when Proportional > need then need else Proportional end as Allocated
  from (
    select
      row_number() over(order by need desc) as RN,
      n.*,
      h.location as Source,
      h.have,
      h.TotalAvail,
      convert(int, floor(h.have * n.need * 1.0 / n.TotalNeed), 0) as Proportional
    from (
      select n.*, sum(need) over (partition by item) as TotalNeed
      from NeedInv n) n
    join (select h.*, sum(have) over (partition by item) as TotalAvail from HaveInv h) h
      on n.item = h.item
      and h.have > 0
    ) n
  ) n
) n
) n
where n.need > 0

它似乎适用于大多数情况,除非Allocated设置为零,但仍有可以转移的项目.这可以在项目200 1中看到,其中位置B仅需要1但将要接收2项目,而C还需要1项目的位置将被接收0.

任何帮助/指导将不胜感激!

Answer 1

IMO，您的查询对于它需要执行的操作来说看起来有点复杂。

据我所知，这只是使用库存总计将逻辑构建到查询中的简单问题。从本质上讲，这只是建立规则的问题，如果你需要的东西可以从源位置获取，你就获取它，否则你就获取尽可能多的东西。

例如，我相信以下查询包含所需的逻辑：

SELECT N.Item,
       SourceLocation = H.Location,
       TargetLocation = N.Location,
       Qty = 
        CASE 
            WHEN N.TotalRunningRequirement <= H.TotalRunningInventory -- If the current source location has enough stock to fill the request.
            THEN 
                CASE
                    WHEN N.TotalRunningRequirement - N.Need < H.TotalRunningInventory - H.Have -- If stock required has already been allocated from elsewhere.
                    THEN N.TotalRunningRequirement - (H.TotalRunningInventory - H.Have) -- Get the total running requirement minus stock allocated from elsewhere.
                    ELSE N.Need -- Otherwise just take how much is needed.
                END
            ELSE N.Need - (N.TotalRunningRequirement - H.TotalRunningInventory) -- Current source doesn't have enough stock to fulfil need, so take as much as possible.
        END
FROM
( 
    SELECT *, TotalRunningRequirement = SUM(need) OVER (PARTITION BY item ORDER BY location)
    FROM NeedInv
    WHERE need > 0
) AS N
JOIN 
(
    SELECT *, TotalRunningInventory = SUM(have) OVER (PARTITION BY item ORDER BY location)
    FROM HaveInv
    WHERE have > 0  
) AS H
    ON H.Item = N.Item
    AND H.TotalRunningInventory - (N.TotalRunningRequirement - N.need) > 0 -- Join if stock in source location can be taken
    AND H.TotalRunningInventory - H.Have - (N.TotalRunningRequirement - N.need) < N.TotalRunningRequirement
;

注意：据我所知，您所需的输出似乎与第 200 项的示例数据不匹配。