glad those scripts are helpful.
you were asking about the 'name' of this process. i'm not 100% sure there is an official 'term' for the way you populate an empty variable string with a result set.
i've always called it "running the result set"
there are a few ways to do this, but it's true; this is the best way for the sake of simplicity.
declare @run_the_result_set varchar(max)
set @run_the_result_set = ''
select @run_the_result_set = @run_the_result_set
+ 'my concatenated query [' + MyColumn + '] whatever else you need; '
this little code snippet could probably found with a dozen different mods. a quick google would give you what you need.