DSum would work-- you also can do subqueries.
My reccollection of subqueries with Access is this--
You can add a subquery and then 'presto' when Access decides that your
query is 'too complex' then it will through a tissy-fit.
That is one of my biggest complaints about MDB.
But you _SHOULD_ be able to do somehting like this
Select OD.*,
(Select Name From Employees E where E.EmployeeID =
OD.SalesPersonID) as SalesPersonName
From OrderDetails OD
Hope that helps--
-Aaron