Sub VeriGuncelle()
     Set rs = CurrentDb.OpenRecordset("select Tablo2")
    With rs
       If Not .BOF And Not .EOF Then
 
           .MoveLast
           .MoveFirst
 
           While (Not .EOF)
           xTplm = DSum("nz(adet2,0)", "tablo2", "RezervNo='" & .Fields(0) & "' AND Kod='" & .Fields(1) & "'")
             rs3 = DLookup("nz(adet2,0)", "tablo1", "RezervNo='" & .Fields(0) & "' AND Kod='" & .Fields(1) & "'")
                If rs3 - xTplm >= rs(2) Then
                     xDgr = rs(2)
                ElseIf rs3 - xTplm < rs(2) And 0 < rs3 - xTplm Then
                     xDgr = rs3 - xTplm
                Else
                     xDgr = 0
                End If
                .Edit
                rs(3) = xDgr
                .Update
               .MoveNext
           Wend
       End If
    End With
End Sub