UFN_CONSTITID_MAPFROM_REGISTRANTREGISTRATIONID

            create function dbo.UFN_CONSTITID_MAPFROM_REGISTRANTREGISTRATIONID
            (
                @REGISTRANTREGISTRATIONID uniqueidentifier
            )
            returns uniqueidentifier
            as
            begin
                declare @ID uniqueidentifier;

                select
                    @ID = REGISTRANT.CONSTITUENTID
                from
                    dbo.REGISTRANTREGISTRATION
                    inner join dbo.REGISTRANT on REGISTRANTREGISTRATION.REGISTRANTID = REGISTRANT.ID
                where
                    REGISTRANTREGISTRATION.ID = @REGISTRANTREGISTRATIONID;

                return @ID;
            end