Convert heavy asp code to run in sql - sql

Question

A bit of asp code which in context does; timeline the product's sales performance based on the start year which product was online to the number of years active, for example a product published on 2000 would have the peak sales for couple of years but by 2004 there would be none...but code this is for all products in the system and grouping by year...(if you questions I can answer them or I think looking at code would give a fair idea on what it's doing !!)
Firstly it runs this query to get the data ( which I want to change ):
SELECT Products.ProductID, Products.AnticipatedSalesPattern, Convert(Char(10),Invoices.Date,103) As [date], Orders.Cost
FROM (Orders INNER JOIN Products ON Orders.ProductID = Products.ProductID)
INNER JOIN Invoices ON Orders.Invoice = Invoices.InvoiceNum
WHERE (Products.IsResource=1 AND Orders.Returned<>1 AND Orders.Cost<>0)
ORDER BY Products.ProductID, Invoices.Date;
Here is how it process the data(in asp), I know it's not effective just made it sample modeling data...
while not dbrecords.eof
RecordsCount = RecordsCount + 1
if dbrecords("ProductID") <> LastPID then
PIDsCount = PIDsCount + 1
LastPID = dbrecords("ProductID")
FirstSaleDate = dbrecords("Date")
if month(FirstSaleDate) < 9 then
FirstSchoolYear = Year(FirstSaleDate) - 1
else
FirstSchoolYear = Year(FirstSaleDate)
end if
end if
YearsSinceFirstSale = int(DateDiff("d",FirstSaleDate,dbrecords("Date"))/365)
MyArray(FirstSchoolYear-2000,YearsSinceFirstSale) = MyArray(FirstSchoolYear-2000,YearsSinceFirstSale) + dbrecords("Cost")
MyArrayTotals(FirstSchoolYear-2000) = MyArrayTotals(FirstSchoolYear-2000) + dbrecords("Cost")
TotalSales = TotalSales + dbrecords("Cost")
dbrecords.movenext
wend
Now what I like is to remove the whole process of putting the data into an array and the query to return the yearly data
What i'm curently stuck on is to write sql to pass the years since first sale and keeping track of each products (how to implement that in sql), I beleieve parameters are accepted via CTE statements...
Also if you think that this can be achieved some other way much effieciently that would be great too
Any help would be greatly appreciated...
So far I got to;
This doesn't provide with the identical data produced by the asp...and also let me know if there is a better way to do this...
DROP VIEW inline_view;
GO
CREATE VIEW inline_view AS
SELECT p2.ProductID, p2.AnticipatedSalesPattern, Invoices.Date, Orders.Cost, case when MONTH(date) < 9 then YEAR(date)-1 else YEAR(date) end as year,
(select top 1 case when MONTH(i.date) < 9 then YEAR(i.date)-1 else YEAR(i.date) end from Invoices i inner join Orders o on i.InvoiceNum=o.Invoice
inner join Products p on o.ProductID = p.ProductID where p2.ProductID = p.productID order by i.Date asc) as startsale
FROM (Orders INNER JOIN Products p2 ON Orders.ProductID = p2.ProductID)
INNER JOIN Invoices ON Orders.Invoice = Invoices.InvoiceNum
WHERE (p2.IsResource=1 AND Orders.Returned<>1 AND Orders.Cost<>0)
;
GO
SELECT * FROM (
select SUM(cost) sum, datediff(y, startsale, year) as year, startsale from inline_view
group by year, startsale
) as data
PIVOT
(
sum(sum)
--years after product is online
FOR year IN ([1], [2], [3],[4],[5],[6],[7],[8],[9], [10],[11], [12])
) as pvt;