Sql server 对采购订单未涵盖的现货需求的查询

我在SQL Server 2014中有两个表

第一个表是原材料的累积需求：

create table #Demand
(
    ItemPN nvarchar(17), /* Part Number, for example "AA-ECN0018" */
    [Period] nvarchar(7), /* Period in format YYYY-MM, for example "2020-01" */
    Qty int  /*  Actual demand */
)

第二个表是采购订单列表：

create table #PurchaseOrders
(
    OrderNumber int, /* P/O number */
    POLine int, /* P/O line number */
    ItemPN nvarchar(17), /* Part Number, for example "AA-ECN0018" */
    CurrentDelDate nvarchar(10), /* Delivery date in format YYYY-MM-DD, for example "2020-01-18" */
    OrderedQty int. /*Qty that has been ordered initially in the Purchase Order line */
    DeliveredQty int, /* Qty in the Purchase Order line that has been already delivered */
    BackOrderQty /* Qty that the supplier has to supply, actually it is OrderedQty - DeliveredQty */
)

我需要找出一个时期（YYYY-MM）范围内现有采购订单行未涵盖的零件号。因此，采购部需要加快这些P/N的采购订单

我计算了每个时期的累计需求：

SUM([Qty]) OVER(PARTITION BY Item ORDER BY Item, [Period] ROWS UNBOUNDED PRECEDING) AS DemandPerPeriod

然后我在p/N和Period上的

#Demand

和

#PurchaseOrders

表之间做了一个左连接：

SELECT 
  d.ItemPN DemandItem
 ,d.[Period] DemandPeriod
 ,t.[OrderNumber] 
 ,t.[POLine]
 ,t.ItemPN
 ,[OrderedQty] - [DeliveredQty] as ActualBackorder
 ,d.DemandPerPeriod
 ,SUM([OrderedQty] - [DeliveredQty]) OVER(PARTITION BY ItemPN ORDER BY ItemPN, CurrentDelDate ROWS UNBOUNDED PRECEDING)  RunningPur
  ,d.DemandPerPeriod -
  SUM([OrderedQty] - [DeliveredQty]) OVER(PARTITION BY ItemPN ORDER BY ItemPN, CurrentDelDate ROWS UNBOUNDED PRECEDING)
  AS NotCoveredDemand
t.CurrentDelDate 
FROM #PurchaseOrders t
  LEFT JOIN (
   SELECT 
    ItemPN
    ,[Period]
    ,QTY
    ,SUM([Qty]) OVER(PARTITION BY Item ORDER BY Item, [Period] ROWS UNBOUNDED PRECEDING)  DemandPerPeriod
  FROM #Demand ) d ON d.ItemPN = t.ItemPN 
            AND d.Period = CONVERT(NVARCHAR(4), YEAR(CurrentDelDate)) + '-' + RIGHT('00' + CONVERT(NVARCHAR(2),  Month(CurrentDelDate)), 2)
  WHERE ROUND(BackorderQty, 0) > 0
  ORDER BY ItemPN, Period

我真正需要的是：

确保我的方法是正确的

找出该月最后一笔未覆盖该月需求的订单

---

可能是这样的：

WITH Demands
AS
(
    SELECT d.ItemPN, [Period], SUM(Qty) AS TotalDemand
    FROM #Demand AS d
    GROUP BY d.ItemPN, [Period] 
),
ExistingOrders
AS
(
    SELECT po.ItemPN, LEFT(po.CurrentDelDate, 7) AS [Period],
           SUM(po.OrderedQty - po.DeliveredQty) AS TotalBackorders
    FROM #PurchaseOrders AS po
    ON d.ItemPN = po.ItemPN 
    AND d.[Period] = LEFT(po.CurrentDelDate, 7)
    GROUP BY po.ItemPN, LEFT(po.CurrentDelDate, 7)
),
UndersuppliedDemand
AS
(
    SELECT d.ItemPN, 
           d.[Period],
           d.TotalDemand - COALESCE(eo.TotalBackorders) AS TotalUndersupplied
    FROM Demands AS d
    LEFT OUTER JOIN ExistingOrders AS eo
    ON d.ItemPN = eo.ItemPN
    AND d.[Period] = eo.[Period]
    WHERE d.TotalDemand > eo.TotalBackorders
)
SELECT ud.ItemPN,
       ud.[Period],
       o.OrderNumber,
       o.POLine
FROM UndersuppliedDemand AS ud
CROSS APPLY 
(
    SELECT po.OrderNumber,
           po.POLine
    FROM #PurchaseOrders AS po
    WHERE po.ItemPN = ud.ItemPN
    AND LEFT(po.CurrentDelDate, 7) = ud.[Period]
    AND po.OrderNumber = (SELECT MAX(pom.OrderNumber) 
                          FROM #PurchaseOrders AS pom
                          WHERE pom.ItemPN = ud.ItemPN
                          AND LEFT(pom.CurrentDelDate, 7) = ud.[Period])
) AS o;

---

（没有数据等无法检查）

谢谢。在

现有订单中

我应该

左外连接
#PurchaseOrders
和
#Demand
吗？我不是那样做的。我首先得到了需求，然后得到了任何现有的订单，然后用这两种方法来确定供应不足的需求。