Create comma seperated list out of a sql query ( tsql )

Surfing the net for a sql answer, I came across something really cool. Below is an example of how to create a comma separated list of values in a single query.

–declare holder var
DECLARE @list VARCHAR(8000)

–build comma separated list
SELECT @list = COALESCE(@list + ‘, ‘, ”) + CAST(track_id AS VARCHAR(5) )
FROM webtool_tracks

–show results
SELECT @list AS ‘list’

The results should look something like this