SQL - 从行中减去一个耗尽的值

Question

我有一种情况，我需要从一个表中获取“消耗的数量”，并将其应用于第二个表，该表有 1 行或更多行是“合并批次”的数量。我不知道如何更好地描述它，这是我从表格的角度来看的意思：

Table Pooled_Lots
----------------------------
Id  Pool    Lot Quantity
1   1       1   5
2   1       2   10
3   1       3   4
4   2       1   7
5   3       1   1
6   3       2   5

Table Pool_Consumption
----------------------------
Id  PoolId  QuantityConsumed
1   1       17
2   2       8
3   3       10

我需要一个来自 SQL 查询的结果行集，如下所示：

Pool    Lot Quantity    QuantityConsumed    RunningQuantity RemainingDemand SurplusOrDeficit
1       1   5           17                  0               12              NULL
1       2   10          17                  0               2               NULL
1       3   4           17                  2               0               2
2       1   7           8                   0               1               -1
3       1   1           10                  0               9               NULL
3       2   5           10                  0               4               -4

因此，Pool_Consumption.QuantityConsumed 需要是从 Pooled_Lots 的行中减去的“消耗值”，其中 Pool_Consumption.PoolId = Pooled_Lots.Pool。我不知道你会如何陈述这样的查询：

• 如果不在最后一行，AmtConsumedFromLot = Quantity - QuantityConsumed if QuantityConsumed
• 如果有更多行，QuantityConsumed = QuantityConsumed - Quantity
• 循环直到最后一行
• 如果最后一行，AmtConsumedFromLot = QuantityConsumed

假设 Id 是主键，目标 DB 是 SQL 2005。

编辑：由于人们宣称我“没有提供足够的信息，请关闭此”这里还有更多： Pool_Consumption 从中提取的 NO 设置批次，它需要从 all Pool_Consumption.PoolId = Pooled_Lots.Pool 的所有批次，直到 QuantityConsumed 完全耗尽或我减去 Pooled_Lots 行的最后一个子集，其中 Pool_Consumption.PoolId = Pooled_Lots.Pool

我不知道该怎么解释。这不是一个家庭作业问题，这不是一个虚构的“思想练习”。我需要帮助来弄清楚如何正确减去多行的 QuantityConsumed！

Answer 1

作为练习留给 OP：根据样本数据找出正确的结果并总结以下查询的结果：

-- Create some test data.
declare @Pooled_Lots as table ( Id int, Pool int, Lot int, Quantity int );
insert into @Pooled_Lots ( Id, Pool, Lot, Quantity ) values
  ( 1, 1, 1, 5 ), ( 2, 1, 2, 10 ), ( 3, 1, 3, 4 ),
  ( 4, 2, 1, 7 ),
  ( 5, 3, 1, 1 ), ( 6, 3, 2, 5 );
declare @Pool_Consumption as table ( Id int, Pool int, QuantityConsumed int );
insert into @Pool_Consumption ( Id, Pool, QuantityConsumed ) values
  ( 1, 1, 17 ), ( 2, 2, 8 ), ( 3, 3, 10 );

select * from @Pooled_Lots order by Pool, Lot;
select * from @Pool_Consumption order by Pool;

with Amos as (
  -- Start with Lot 1 for each Pool.
  select PL.Pool, PL.Lot, PL.Quantity, PC.QuantityConsumed,
    case
      when PC.QuantityConsumed is NULL then PL.Quantity
      when PL.Quantity >= PC.QuantityConsumed then PL.Quantity - PC.QuantityConsumed
      when PL.Quantity < PC.QuantityConsumed then 0
      end as RunningQuantity,
    case
      when PC.QuantityConsumed is NULL then 0
      when PL.Quantity >= PC.QuantityConsumed then 0
      when PL.Quantity < PC.QuantityConsumed then PC.QuantityConsumed - PL.Quantity
      end as RemainingDemand
    from @Pooled_Lots as PL left outer join
      @Pool_Consumption as PC on PC.Pool = PL.Pool
    where Lot = 1
  union all
  -- Add the next Lot for each Pool.
  select PL.Pool, PL.Lot, PL.Quantity, CTE.QuantityConsumed,
    case
      when CTE.RunningQuantity + PL.Quantity >= CTE.RemainingDemand then CTE.RunningQuantity + PL.Quantity - CTE.RemainingDemand
      when CTE.RunningQuantity + PL.Quantity < CTE.RemainingDemand then 0
      end,
    case
      when CTE.RunningQuantity + PL.Quantity >= CTE.RemainingDemand then 0
      when CTE.RunningQuantity + PL.Quantity < CTE.RemainingDemand then CTE.RemainingDemand - CTE.RunningQuantity - PL.Quantity
      end
    from Amos as CTE inner join
      @Pooled_Lots as PL on PL.Pool = CTE.Pool and PL.Lot = CTE.Lot + 1
  )
select *,
  case
    when Lot = ( select max( Lot ) from @Pooled_Lots where Pool = Amos.Pool ) then RunningQuantity - RemainingDemand
    else NULL end as SurplusOrDeficit
  from Amos
  order by Pool, Lot;

Answer 2

（基于问题的第 4 版，因为我的 WiFi 中断了很长一段时间）

(SELECT
  Pool,
  SUM(Quantity) as Pool_Quantity
FROM
  Pooled_Lots
GROUP BY
  Pool) as Pool_Quantity_Table

现在您有一个将池数量汇总为单个值的表。

现在是完整的查询：

SELECT
  Pool_Consumption.PoolID as Pool,
  Pool_Quantity_Table.Pool_Quantity as Quantity,
  Pool_Consumption.QuantityConsumed as AmtConsumedFromLot,
  (Pool_Quantity_Table.Pool_Quantity - Pool_Consumption.QuantityConsumed) as SurplusOrDefecit
FROM
  Pool_Consumption
INNER JOIN
  (SELECT
    Pool,
    SUM(Quantity) as Pool_Quantity
  FROM
    Pooled_Lots
  GROUP BY
    Pool) as Pool_Quantity_Table
ON (Pool_Consumption.PoolID = Pool_Quantity_Table.Pool);