SELECT *, (
            SELECT LAST(DEGER) FROM (
                      SELECT ABONE, TARIH, DEGER FROM  TabloAdi 
                             WHERE TARIH BETWEEN #3/1/2011# AND #3/4/2011#) )
             -
              (
             SELECT FIRST(DEGER) FROM (
                      SELECT ABONE, TARIH, DEGER FROM  TabloAdi 
                             WHERE TARIH BETWEEN #3/1/2011# AND #3/4/2011#) ) AS fark 
FROM TabloAdi
 
WHERE TARIH BETWEEN #3/1/2011# AND #3/4/2011#

Dim ilk, son As Integer
Dim bb As New ADODB.Recordset
 
bb.Open "select * from Tablo_Adi where Tarih between #01/01/2011# And #12/12/2011#", _
CurrentProject.Connection ' Tablo ismini düzeltiniz.
 
ilk = bb("Deger") ' Deger tablodaki istenilen alanın adıdır. 
bb.MoveLast
son = bb("Deger")
 
msgbox (son - ilk)  ' Nereye almak istiyorsanız burayı düzenleyiniz.
 
bb.Close