我试图找到可以与“需求”（负交易量）相匹配的“补货”（交易量为正）。
基本逻辑是：对于给定的需求，找到第一个可用的补货（该补货是来自现有库存还是来自即将发生的变更）。
我正在使用如下所示的表dbo_purchases_new：
| Element_ID | Element | Transaction_Date | Transaction_Quantity | Total_Inventory |
|:----------:|:----------:|:----------------:|:--------------------:|:---------------:|
| | STOCK | | 5 | 5 |
| MO302 | Make_Order | 1/3/2019 | 1 | 6 |
| SO105 | Sale | 2/1/2019 | -1 | 5 |
| SO106 | Sale | 2/1/2019 | -1 | 4 |
| MO323 | Make_Order | 2/2/2019 | 1 | 5 |
| SO107 | Sale | 2/4/2019 | -1 | 4 |
| SO191 | Sale | 2/5/2019 | -1 | 3 |
| SO123 | Sale | 2/6/2019 | -1 | 2 |
| SO166 | Sale | 3/1/2019 | -1 | 1 |
| SO819 | Sale | 3/5/2019 | -1 | 0 |
| SO603 | Sale | 3/10/2019 | -4 | -3 |
| MO400 | Make_Order | 3/15/2019 | 1 | -2 |
| MO459 | Make_Order | 3/15/2019 | 1 | -1 |
| MO460 | Make_Order | 3/18/2019 | 1 | 0 |
| MO491 | Make_Order | 3/19/2019 | 1 | 1 |
| MO715 | Make_Order | 4/1/2019 | 3 | 4 |
| SO100 | Sale | 4/2/2019 | -1 | 3 |
| SO322 | Sale | 4/3/2019 | -1 | 2 |
| SO874 | Sale | 4/4/2019 | -1 | 1 |
| SO222 | Sale | 4/5/2019 | -1 | 0 |
| MO999 | Make_Order | 4/5/2019 | 1 | 1 |
| SO999 | Sale | 4/6/2019 | -1 | 0 |
。
我现在正尝试通过跟踪Make_Order来跟踪哪个Sale将履行哪个Transaction_Quantity。
理想情况下，结果数据集将如下所示，其中Replenishment和Replenishment_Date是新添加的列：
| Element_ID | Element | Transaction_Date | Transaction_Quantity | Total_Inventory | Replenishment | Replenishment_Date |
|:----------:|:----------:|:----------------:|:--------------------:|:---------------:|:-------------:|:------------------:|
| | STOCK | | 5 | 5 | NULL | NULL |
| MO302 | Make_Order | 1/3/2019 | 1 | 6 | NULL | NULL |
| SO105 | Sale | 2/1/2019 | -1 | 5 | STOCK | NULL |
| SO106 | Sale | 2/1/2019 | -1 | 4 | STOCK | NULL |
| MO323 | Make_Order | 2/2/2019 | 1 | 5 | NULL | NULL |
| SO107 | Sale | 2/4/2019 | -1 | 4 | STOCK | NULL |
| SO191 | Sale | 2/5/2019 | -1 | 3 | STOCK | NULL |
| SO123 | Sale | 2/6/2019 | -1 | 2 | STOCK | NULL |
| SO166 | Sale | 3/1/2019 | -1 | 1 | MO302 | 1/3/2019 |
| SO819 | Sale | 3/5/2019 | -1 | 0 | MO323 | 2/2/2019 |
| SO603 | Sale | 3/10/2019 | -4 | -3 | MO460 | 3/18/2019 |
| MO400 | Make_Order | 3/15/2019 | 1 | -2 | NULL | NULL |
| MO459 | Make_Order | 3/15/2019 | 1 | -1 | NULL | |
| MO460 | Make_Order | 3/18/2019 | 1 | 0 | NULL | NULL |
| MO491 | Make_Order | 3/19/2019 | 1 | 1 | NULL | NULL |
| MO715 | Make_Order | 4/1/2019 | 3 | 4 | NULL | NULL |
| SO100 | Sale | 4/2/2019 | -1 | 3 | MO491 | 3/19/2019 |
| SO322 | Sale | 4/3/2019 | -1 | 2 | MO715 | 4/1/2019 |
| SO874 | Sale | 4/4/2019 | -1 | 1 | MO715 | 4/1/2019 |
| SO222 | Sale | 4/5/2019 | -1 | 0 | MO715 | 4/1/2019 |
| MO999 | Make_Order | 4/5/2019 | 1 | 1 | NULL | NULL |
| SO999 | Sale | 4/6/2019 | -1 | 0 | SO999 | 4/5/2019 |
规则集实质上是： 对于给定的需求（任意值的负交易量），找到哪个补货（任意值的正交易量）满足要求。
我对如何实现这一目标感到非常困惑。我想一些伪代码看起来像：
for curr in transaction_quantity:
if curr < 0:
if stock.exists() and stock.notempty():
fill in data from that
else:
find next replenishment
fill in data from that
else:
next
现在，到目前为止，我已经知道了，但是我知道它不会运行。我对从这里去哪里很困惑。我尝试查看帖子like this，但没有答案。然后我tried looking up CURSOR，但这令我感到困惑，我不确定如何将其应用于此问题。
/****** WiP Script ******/
SELECT
[jerry].[dbo].[purchases_new].*,
CASE WHEN Transaction_Quantity < 0 THEN -- (SELECT Element_ID FROM the_current_row WHERE transaction_quantity > 0)
ELSE NULL AS "Replenishment",
-- (SELECT Transaction_Date FROM [jerry].[dbo].[purchases_new] WHERE Element_ID
-- Not sure how to grab the correct date of the element id from the column before
FROM
[jerry].[dbo].[purchases_new]
感谢您的协助。我一直在努力解决这个问题。注释包含其他信息。 注意-由于用户要求提供更多信息，我一直在尝试更新此问题。
答案 0 :(得分：1)
这是一次尝试。如果您需要支持> 1的交易增量/减量，则需要使用另一层抽象来进行抵消。它基本上使销售顺序与借方顺序对齐，然后将其用作连接回到主数据集。
想法是将加法和减法分为两组，按组先后顺序排列，同时还要记住每个项目的顺序回到主列表中。这样，您可以将每个减法与最近的加法对齐。在处理1时，这非常简单。
编辑->处理值> 1。
计算Transaction_Amount>（+/-）1会增加一点复杂度，但仍然可以解决。现在，我们需要扩展由Transaction_Amount设置的每个加减交易，因此将数据集加长，但是，原始算法仍将应用于现在更长的数据集。这将允许记录“部分完成”。因此(12 A 5)等于(12 A 1), (12 A 1), (12 A 1), (12 A 1), (12 A 1)。现在，当减法器以类似的方式加长时（所有行的顺序与序列的第一个相同），对齐仍然有效，并且加法和减法可以与最近的邻居进行匹配。
DECLARE @T TABLE(Element_ID NVARCHAR(50),Element NVARCHAR(50), Transaction_Date DATETIME,Transaction_Quantity INT,Total_Inventory INT)
INSERT @T VALUES
('MO301','Make_Order','1/1/2019',5,1),
('MO302','Make_Order','1/3/2019',1,2),
('SO105','Sale','2/1/2019',-2,1),
('SO106','Sale','2/1/2019',-1,0),
('MO323','Make_Order','2/2/2019',1,1),
('SO107','Sale','2/4/2019',-1,0),
('SO191','Sale','2/5/2019',-1,-1),
('SO123','Sale','2/6/2019',-1,-2),
('SO166','Sale','3/1/2019',-1,-3),
('SO603','Sale','3/2/2019',-1,-4),
('MO400','Make_Order','3/15/2019',1,-3),
('MO459','Make_Order','3/15/2019',1,-2),
('MO460','Make_Order','3/18/2019',1,-1),
('MO491','Make_Order','3/19/2019',1,0)
;WITH Normalized AS
(
SELECT *, RowNumber = ROW_NUMBER() OVER (ORDER BY (SELECT 0)), IsAdd = CASE WHEN Transaction_Quantity>0 THEN 1 ELSE 0 END FROM @T
)
,ReplicateAmount AS
(
SELECT Element_ID, Element, Transaction_Date, Transaction_Quantity=ABS(Transaction_Quantity) ,Total_Inventory, RowNumber, IsAdd
FROM Normalized
UNION ALL
SELECT R.Element_ID, R.Element, R.Transaction_Date, Transaction_Quantity=(R.Transaction_Quantity - 1), R.Total_Inventory, R.RowNumber, R.IsAdd
FROM ReplicateAmount R INNER JOIN Normalized N ON R.RowNumber = N.RowNumber
WHERE ABS(R.Transaction_Quantity) > 1
)
,NormalizedAgain AS
(
SELECT Element_ID, Element, Transaction_Date, Transaction_Quantity=1, Total_Inventory, RowNumber = ROW_NUMBER() OVER (ORDER BY RowNumber), IsAdd FROM ReplicateAmount
)
,Additives AS
(
SELECT *, AddedOrder = ROW_NUMBER() OVER (ORDER BY (SELECT 0)) FROM NormalizedAgain WHERE IsAdd=1
)
,Subtractions AS
(
SELECT Element_ID, Element, Transaction_Date, Transaction_Quantity=-1 , Total_Inventory, RowNumber, SubtractedOrder = ROW_NUMBER() OVER (ORDER BY (SELECT 0))FROM NormalizedAgain WHERE IsAdd=0
)
,WithTies AS
(
SELECT
S.RowNumber,
S.Element_ID,
BoughtFromRowNumber = A.RowNumber,
SoldToID =S.Element_ID,
BoughFromID=A.Element_ID,
S.Element,
S.Transaction_Date,
S.Transaction_Quantity,
S.Total_Inventory
FROM
Additives A
LEFT OUTER JOIN Subtractions S ON A.AddedOrder=S.SubtractedOrder
UNION
SELECT
A.RowNumber,
A.Element_ID,
BoughtFromRowNumber = S.RowNumber,
SoldToID = NULL,
BoughFromID=NULL,
A.Element,
A.Transaction_Date,
A.Transaction_Quantity,
A.Total_Inventory
FROM
Additives A
LEFT OUTER JOIN Subtractions S ON A.AddedOrder=S.SubtractedOrder
)
SELECT
T.RowNumber,
T.Element_ID,
T.Element,
T.Transaction_Date,
T.Transaction_Quantity,
T.Total_Inventory,
T2.SoldToID,
T.BoughFromID
FROM
WithTies T
LEFT OUTER JOIN WithTies T2 ON T2.BoughtFromRowNumber= T.RowNumber
WHERE
NOT T.RowNumber IS NULL
ORDER BY
T.RowNumber