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SQL - subtracting an exhaustive value from rows

I have a situation where I need to take the “quantity consumed” from one table and apply it to a second table with 1 or more rows that are “combined” in quantities. I'm not sure how to describe it better, here is what I mean from the table:

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

I need a result set of rows from an SQL query that will look like this:

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

So Pool_Consumption.QuantityConsumed should be the "depleting value" subtracted from the rows from Pooled_Lots, where Pool_Consumption.PoolId = Pooled_Lots.Pool. I can't figure out how you would specify a query that says:

  • If not on the last line, AmtConsumedFromLot = Quantity - QuantityConsumed if QuantityConsumed <Quantity, another Quantity
  • , QuantityConsumed = QuantityConsumed - Quantity
  • , AmtConsumedFromLot = QuantityConsumed

, Id , - SQL 2005.

: , " , , ". : , Pool_Consumption, , Pool_Consumption.PoolId = Pooled_Lots. , , QuantityConsumed Pooled_Lots, Pool_Consumption.PoolId = Pooled_Lots.Pool

, . , , "". , , QuantityConsumed !

+5
2

OP: , , :

-- 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
+7

( 4 , Wi-Fi )

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

, .

:

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);
+1

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