Daca lucrezi pe SQL 2005 poti incerca sa adaptezi acest exemplu (pentru care am folosit AdventureWorks)
SELECT
soh.SalesOrderID, sod.SalesOrderDetailID, sod.ProductID, sod.OrderQty,
ROW_NUMBER() OVER (PARTITION BY soh.SalesOrderID ORDER BY sod.SalesOrderDetailID) AS Pos
FROM
Sales.SalesOrderHeader soh JOIN Sales.SalesOrderDetail sod
ON
soh.SalesOrderID = sod.SalesOrderID