Anyway to do this in TSQL (2005) without a cursor?

using SQL Server 2005;

I have two tables: Demand and Supply.  I need to determine for each record in the demand table which record in supply table it can consume.

These are the demand and supply table and sample data.

CREATE TABLE Demand
( Priority INT,
Food VARCHAR(10),
      Qty INT)
      
INSERT INTO Demand
      Select 1, 'Apples', 2
      UNION ALL
      Select 2, 'Apples', 5
      UNION ALL
      Select 3, 'Apples', 4
      UNION ALL
      Select 4, 'Apples', 10
      UNION ALL
      Select 5, 'Apples', 15


CREATE TABLE Supply
( SourceID INT,
Food VARCHAR(10),
      Qty INT)
      
INSERT INTO Supply
      Select 1, 'Apples', 10
      UNION ALL
      Select 2, 'Apples', 20
      UNION ALL
      Select 3, 'Apples', 5


----------------------------------
The end result I'm trying to obtain is like so:
Priority      Food      Qty            SupplyID
1      Apples      2            1
2      Apples      5            1
3      Apples      4            2
4      Apples      10            2
5      Apples      15            NULL

Thanks,
sopheak
sopheakAsked:
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Kevin CrossConnect With a Mentor Chief Technology OfficerCommented:
Check the views independently and make sure the total demands look correct.  Should go 2, 7, 11, and so on.  I will check when I get home as I have this data loaded there and I got results you requested when I tested last night.
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sopheakAuthor Commented:
I guess it would be okay to use a cursor in answer too, it may be faster depending on the amount of data.
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Kevin CrossChief Technology OfficerCommented:
I don't have my SQL Management Studio, but this should parse out fine.
-- create a view for demand
CREATE VIEW dbo.vw_DemandTotalsByFoodAndPriority AS
;WITH demandCTE AS (
    SELECT *, row_number() OVER (PARTITION BY Food ORDER BY Priority) As dRow
    FROM Demand
)
SELECT d1.Food, d1.Priority, d1.Qty, d1.Qty + IsNull(d2.Qty, 0) AS TotalDemand
FROM demandCTE d1 LEFT JOIN demandCTE d2
ON d1.Food = d2.Food AND d1.dRow - 1 = d2.dRow;
GO
 
-- create a view for supply
CREATE VIEW vw_SupplyTotalsByFoodAndSourceID AS
;WITH supplyCTE AS (
    SELECT *, row_number() OVER (PARTITION BY Food ORDER BY SourceID) As sRow
    FROM Supply
)
SELECT s1.Food, s1.SourceID, s1.Qty, s1.Qty + IsNull(s2.Qty, 0) AS TotalSupply
FROM supplyCTE s1 LEFT JOIN supplyCTE s2
ON s1.Food = s2.Food AND s1.sRow - 1 = s2.sRow;
GO
 
SELECT d.Priority, d.Food, d1.Qty, s.SourceID
FROM vw_DemandTotalsByFoodAndPriority d LEFT JOIN vw_SupplyTotalsByFoodAndSourceID s
ON d.Food = s.Food AND d.TotalDemand <= s.TotalSupply
ORDER BY 2, 1

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Kevin CrossChief Technology OfficerCommented:
Sorry,filled with type-o's -- use THIS:
-- create a view for demand
CREATE VIEW dbo.vw_DemandTotalsByFoodAndPriority AS
WITH demandCTE AS (
    SELECT *, row_number() OVER (PARTITION BY Food ORDER BY Priority) As dRow
    FROM Demand
)
SELECT d1.Food, d1.Priority, d1.Qty, d1.Qty + IsNull(d2.Qty, 0) AS TotalDemand
FROM demandCTE d1 LEFT JOIN demandCTE d2
ON d1.Food = d2.Food AND d1.dRow - 1 = d2.dRow;
 
-- create a view for supply
CREATE VIEW vw_SupplyTotalsByFoodAndSourceID AS
WITH supplyCTE AS (
    SELECT *, row_number() OVER (PARTITION BY Food ORDER BY SourceID) As sRow
    FROM Supply
)
SELECT s1.Food, s1.SourceID, s1.Qty, s1.Qty + IsNull(s2.Qty, 0) AS TotalSupply
FROM supplyCTE s1 LEFT JOIN supplyCTE s2
ON s1.Food = s2.Food AND s1.sRow - 1 = s2.sRow;
 
SELECT        Priority, Food, Qty,
                             (SELECT        MIN(SourceID) AS Expr1
                               FROM            vw_SupplyTotalsByFoodAndSourceID AS s
                               WHERE        (d.Food = Food) AND (d.TotalDemand <= TotalSupply)) AS SupplyID
FROM            vw_DemandTotalsByFoodAndPriority AS d
ORDER BY Food, Priority

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sopheakAuthor Commented:
unfortunately the results don't come out correct;  this is the result from your solution.  For Example, record 3 cannot pull from supplyID 1 because record 1 and 2 already consumed a total of 9 ,so only one is left.  Record 3 should pull the remainder from supplyid 2.

I guess I need to clarify that I want the last supply line a record would pull from to satify the demand.

tahnks

Priority      Food      Qty      SupplyID
1      Apples      2      1
2      Apples      5      1
3      Apples      4      1
4      Apples      10      2
5      Apples      15      2

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Kevin CrossChief Technology OfficerCommented:
Sorry I posted the wrong code version... I will post in a few minutes.
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sopheakAuthor Commented:
I modified your Demand view and it works now:

CREATE VIEW dbo.vw_DemandTotalsByFoodAndPriority AS
WITH demandCTE AS (
    SELECT *, row_number() OVER (PARTITION BY Food ORDER BY Priority) As dRow
    FROM Demand
)
SELECT  d1.Food,
        d1.Priority,
        d1.Qty,
        (SELECT SUM(Qty)
            FROM demandCTE
            WHERE d1.Food = Food AND d1.dRow >= dRow) AS 'TotalDemand'
FROM    demandCTE d1
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Kevin CrossChief Technology OfficerCommented:
This is what I meant to post, sorry!
DROP VIEW vw_SupplyTotalsByFoodAndSourceID
GO
DROP VIEW vw_DemandTotalsByFoodAndPriority
GO
 
-- create a view for demand
CREATE VIEW dbo.vw_DemandTotalsByFoodAndPriority AS
SELECT d1.Food, d1.Priority, d1.Qty
, d1.Qty + IsNull((SELECT SUM(QTY) FROM demand d2 WHERE d2.Food = d1.Food AND d2.Priority < d1.Priority ), 0) AS TotalDemand
FROM demand d1;
 GO
-- create a view for supply
CREATE VIEW vw_SupplyTotalsByFoodAndSourceID AS
SELECT s1.Food, s1.SourceID, s1.Qty
, s1.Qty + IsNull((SELECT SUM(QTY) FROM supply s2 WHERE s1.Food = s2.Food AND s2.SourceID < s1.SourceID ), 0) AS TotalSupply
FROM supply s1
 GO
 
SELECT        Priority, Food, Qty,
                             (SELECT        MIN(SourceID) AS Expr1
                               FROM            vw_SupplyTotalsByFoodAndSourceID AS s
                               WHERE        (d.Food = Food) AND (d.TotalDemand <= TotalSupply)) AS SupplyID
FROM            vw_DemandTotalsByFoodAndPriority AS d
ORDER BY Food, Priority

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Kevin CrossChief Technology OfficerCommented:
Glad you figured it out as well.  I apologize as I saw that needed to include all the rows previous to current one instead of the last one.  
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