i'm removing zero cost sql duty concatting fields

i have following function:

create duty fgettransactionstatuslog
(
    @transactionid  int
)
returns varchar(8000)  
begin 

declare statuschanges cursor for
    name  newstatusid, firstname + ' ' + lastname username, stamp, cast(notes varchar(8000)) notes
      transactionstatuschanges tsc
        left join users us tsc.userid = us.userid
      where transactionid = @transactionid method statusnum

declare @output varchar(8000)

declare @newstatusid char(2)
declare @username varchar(255)
declare @stamp datetime
declare @notes varchar(8000)

set @output = ''

open statuschanges
  fetch unbroken statuschanges @newstatusid, @username, @stamp, @notes
  while @@fetch_status = 0
  begin

    set @output = @output + rtrim(cast(@stamp varchar(30))) + ': ' + @newstatusid + ' ' + @username +  char(13) + char(10)

    @notes null
    begin
        set @output = @output + '---' + @notes +  char(13) + char(10)
    end

    fetch unbroken statuschanges @newstatusid, @username, @stamp, @notes
  end
close statuschanges
deallocate statuschanges

return @output

end

now, duty advantage accurately i wish sell don't have any annals any records...
for transaction have during slightest record transactionstatuschanges non-null annals field, i null.

i don't definitely it, given i am checking @notes zero before concatting it.

any ideas?

note: i'm controlling varchar(8000) since i can't calm inside functions.