Question

I have data that looks like this.

SoldToRetailer

OrderDate  | Customer  | Product  | price | units
-------------------------------------------------
1-jun-2011 | customer1 | Product1 | $10   | 5
2-jun-2011 | customer1 | Product1 | $5    | 3
3-jun-2011 | customer1 | Product2 | $10   | 4
4-jun-2011 | customer1 | Product1 | $4    | 4
5-jun-2011 | customer2 | Product3 | $10   | 1

SalesByRetailers

Customer  | Product  | units
-----------------------------
customer1 | Product1 | 5
customer2 | Product3 | 1

Here’s what I need.

Sales(average price)

Customer  | Product  | units | Average Price
--------------------------------------------
customer1 | Product1 | 5     | $3.44
customer2 | Product3 | 1     | $10

Average Price is defined as the average price of the most recent SoldToRetailer Prices that add up to the units.

So in the first case, I grab the orders from June 4th and June 2nd. I don’t need (actually want) the orders from june 1st to be included.

EDIT: Hopefully a better explanation.

I’m attempting to determine the correct (most recent) price where an item was sold to a retailer. It’s LIFO order for the prices. The price is determined by averaging the price sold over the last n orders. Where n = total retail sales for a particular product and customer.

In SQL pseudcode it would look like this.

Select s1.Customer, s1.product, average(s2.price)
from SalesByRetailers s1
join SoldToRetailer s2
on s1.customer=s2.customer
and s1.product=s2.product
and ( select top (count of records where s2.units = s1.units) from s2 order by OrderDate desc)

What I need to return is the number of records from SoldToRetailer where the sum of units is >= SalesByRetailer Units.

It looks like it could be solved by a RANK or rowover partition, but I’m at a loss.

The SoldToRetailer table is ginormous so performance is at a premium.

Running on SQL 2008R2
Thanks for helping

Answer 1

So I used 3 techniques. First I created a table with an over by clause to give me a sorted list of products and prices, then I edited the table to add in the running average. An OUTER APPLY sub select fixded my final problem. Hopefully the code will help someone else with a similar problem.

A shout out to Jeff Moden of SQLSderverCentral.com fame for the running average help.

     SELECT d.ProductKey,
         d.ActualDollars,
         d.Units,
         ROW_NUMBER() OVER(PARTITION BY ProductKey ORDER BY d.OrderDateKey DESC) AS RowNumber,
         NULL                                                                  AS RunningTotal,
         CONVERT(DECIMAL(10, 4), 0)                                            AS RunningDollarsSum,
         CONVERT(DECIMAL(10, 4), 0)                                            AS RunningAverage
  INTO   #CustomerOrdersDetails
  FROM   dbo.orders d
  WHERE  customerKey = @CustomerToSelect

  --DB EDIT...  Google "Quirky update SQL Server central.  Jeff Moden's version of a
  --Running total.  Holy crap it's faster.  tried trangular joins before. 
  CREATE CLUSTERED INDEX [Index1]
    ON #CustomerOrdersDetails ( ProductKey ASC, RowNumber ASC )

  DECLARE @RunningTotal INT
  DECLARE @PrevProductKey INT
  DECLARE @RunningDollarsSum DECIMAL(10, 4)

  UPDATE #CustomerOrdersDetails
  SET    @RunningTotal = RunningTotal = CASE
                                          WHEN ProductKey = @PrevProductKey THEN c.Units + ISNULL(@RunningTotal, 0)
                                          ELSE c.Units
                                        END,
         @RunningDollarsSum = RunningDollarsSum = CASE
                                                    WHEN ProductKey = @PrevProductKey THEN c.ActualDollars + ISNULL(@RunningDollarsSum, 0)
                                                    ELSE c.ActualDollars
                                                  END,
         @PrevProductKey = ProductKey,
         RunningAverage = @RunningDollarsSum / NULLIF(@RunningTotal, 0)
  FROM   #CustomerOrdersDetails c WITH (TABLOCKX)
  OPTION (MAXDOP 1)

  -- =============================================
  -- Update Cost fields with average price calculation
  -- =============================================
  UPDATE d
  SET    DolSoldCostUSD = COALESCE(d.DolSoldCostUSD,
                                   d.UnitsSold * a.RunningAverage),
  FROM   dbo.inbound d
         OUTER APPLY (SELECT TOP 1 *
                      FROM   #CustomerOrdersDetails ap
                      WHERE  ap.ProductKey = d.ProductKey
                             AND d.UnitsSold + d.UnitsOnHand + d.UnitsOnOrder + d.UnitsReceived + d.UnitsReturned >= RunningTotal
                      ORDER  BY RunningTotal) AS a