If the you looking for Duplicates based on productids then this should work:

select COUNT(tmpOrders.productid) as duplicates,tmpOrders.productid,tmpOrders.productclass,tmpOrders.OrderDate,tmpOrders.ProductType

from tmpOrders

group by tmpOrders.productid,tmpOrders.productclass,tmpOrders.OrderDate,tmpOrders.ProductType

having COUNT(tmpOrders.productid)>1