update Buton set Buton.StokNo=STOKKARTI.StokNo from   Buton 
inner join STOKKARTI on STOKKARTI.Barkodu=Buton.ButonDegeri
Where (Buton.FormAdi = 'HPerakende') AND (Buton.ButonDegeri IS NOT NULL) AND (Buton.ButonDegeri <> '')