UFN_INSTALLMENT_GETINSTALLMENTAMOUNTAPPLIED

            CREATE function dbo.UFN_INSTALLMENT_GETINSTALLMENTAMOUNTAPPLIED
            (
                @INSTALLMENTID uniqueidentifier    
            )
            returns money
            with execute as caller
            as begin
                declare @RETVAL money;

                select 
                    @RETVAL = (coalesce((select sum(INSTALLMENTPAYMENT.AMOUNT) from dbo.INSTALLMENTPAYMENT where INSTALLMENTPAYMENT.INSTALLMENTID = @INSTALLMENTID), 0) + coalesce((select sum(INSTALLMENTWRITEOFF.TRANSACTIONAMOUNT) from dbo.INSTALLMENTWRITEOFF where INSTALLMENTWRITEOFF.INSTALLMENTID = @INSTALLMENTID), 0))
                from 
                    dbo.INSTALLMENT 
                where 
                    INSTALLMENT.ID = @INSTALLMENTID;

                return @RETVAL;
            end