First of all thank you for your help,
I wrote this =Nz(DSum("[SASIA]","hyrje per log cmim mes","[PRODUCT H NAME]=" & [PRODUCT D NAME] & " and[DATA]<=#" & Format([ forms!FATURE SHITJE!DAT SH],"mm/dd/yyyy") & "#"),0) where [PRODUCT D NAME] is in sub form where i am writing and forms!FATURE...