UFN_CAMPAIGN_GETUSERID

                create function dbo.UFN_CAMPAIGN_GETUSERID (
                    @ID uniqueidentifier
                ) returns nvarchar(100)
                as
                begin

                    declare @USERID nvarchar(100);
                    set @USERID = '';

                    select
                        @USERID = CAMPAIGN.USERID
                    from
                        dbo.CAMPAIGN
                    where
                        CAMPAIGN.ID = @ID;

                    return @USERID;
                end