-- create temporary table
create table #temp (seq int identity(1,1), note text)

-- insert dummy data
insert into #temp(note)
select 'This is text dataType data!'

-- Error
select seq
	 , note
	 , note+' add varchar dataType.' as add_note
  from #temp

-- Success
select seq
	 , note
	 , convert(text, convert(varchar(max),note)+' add varchar dataType.') as add_note
  from #temp

▶ Error 인 경우

▶ Success 인 경우