Questions Sum iff total amount

Hi Everyone

I checked on forum to gather more information on the my issue but i dont seem to find the solution

my column show the total interest per different codes. but i only want to look at the total of 2 codes

my column fomula is

=IIf([LMTransactionCode.TranCodeCD]='100',[LMTran.BaseTranAmount],
IIf([LMTransactionCode.TranCodeCD]='101',[LMTran.BaseTranAmount] ,'0,00')) and this is working perfertly fine

and to get the total i tried

=Sum (IIf([LMTransactionCode.TranCodeCD]='100',[LMTran.BaseTranAmount],
IIf([LMTransactionCode.TranCodeCD]='101',[LMTran.BaseTranAmount] ,'0,00')))

=IIf([LMTransactionCode.TranCodeCD]='100','101',sum([LMTran.BaseTranAmount]),'0,00')

and they are not working

what is the best approach to resolve this issue?

Please assist