hvordan man viser tilsvarende post fra adgang baseret på anden kolonne i Datagrid i vb6

Du kan bruge en forespørgsel som sådan:

SELECT subjectcode.Year1, subjectcode.Year2, 
       subjectcode.Subjectcode, subjectcode.Subjectname, 
       subjectcode.Theory_Practical, q.fee
FROM subjectcode 
INNER JOIN (
       SELECT fees.Year1, fees.Year2, "Theory" As FeeType, 
              fees.Theoryfee As Fee
       FROM fees
       UNION ALL
       SELECT fees.Year1, fees.Year2, "Practical" As FeeType, 
              fees.Practicalfee As Fee
       FROM fees)  AS q 
ON (subjectcode.Theory_Practical = q.FeeType) 
   AND (subjectcode.Year2 = q.Year2) 
   AND (subjectcode.Year1 = q.Year1)

Du ville dog være meget bedre stillet ved at omdesigne din gebyrtabel, så den matcher de data, der returneres af den indre sql, det vil sige en anden linje for teori og praktiske gebyrer:

Year1   Year2   FeeType     Fee
2001    2003    Theory      440
2001    2003    Practical   320