UFN_RESERVATION_GETRATESCALEPRICE

        CREATE function dbo.UFN_RESERVATION_GETRATESCALEPRICE
        (
            @ID uniqueidentifier
        )
        returns uniqueidentifier
        with execute as caller
        as 
        begin
            declare @ITINERARYATTENDEECOUNT smallint
            select 
                @ITINERARYATTENDEECOUNT = isnull(sum(QUANTITY),0)
            from dbo.ITINERARYATTENDEE
            inner join dbo.ITINERARY on
                ITINERARY.ID = ITINERARYATTENDEE.ITINERARYID
            inner join dbo.RESERVATION on
                RESERVATION.ID = ITINERARY.RESERVATIONID
            where
                RESERVATION.ID = @ID

            declare @RESERVATIONRATESCALEPRICEID uniqueidentifier = null;

            select
                @RESERVATIONRATESCALEPRICEID = RESERVATIONRATESCALEPRICE.ID
            from dbo.RESERVATIONRATESCALEPRICE
            inner join dbo.RESERVATIONRATESCALE on
                RESERVATIONRATESCALE.ID = RESERVATIONRATESCALEPRICE.RESERVATIONRATESCALEID
            where
                RESERVATIONRATESCALE.ID = @ID and
                @ITINERARYATTENDEECOUNT >= GROUPMINIMUM and
                (
                    @ITINERARYATTENDEECOUNT <= GROUPMAXIMUM or
                    GROUPMAXIMUM = -1
                )

            return @RESERVATIONRATESCALEPRICEID
        end