SELECT A.*, Nz(IIf([A].[SON_KM]-(SELECT Last(SON_KM.SON_KM) AS SonSON_KM

FROM SON_KM

WHERE (SON_KM.SON_KM_ID)<A.SON_KM_ID)<0,0,[A].[SON_KM]-(SELECT Last(SON_KM.SON_KM) AS SonSON_KM

FROM SON_KM

WHERE (SON_KM.SON_KM_ID)<A.SON_KM_ID)),0) AS [Kalan Hesabı]

FROM SON_KM AS A;