case when then end

select
sum(case  when lcc.iCurrencyID=1  then  lcc.iNumber*fUnitprice
                       else  lcc.iNumber*lcc.fUnitprice*lcc.fExchangeRate end)
            ,0) as a
 from  lccomeslist  as  lcc  where  istatus=1
  and lcc.iLCContractID  in
  (
 select cml.iLCContractID from CmLCContract as cml
    where cml.istatus=1 and cml.iLoanCustomerID = 1
   )