Get comma seperated values with help of XML Path

SELECT Column1,
 SUBSTRING(
 (
  SELECT ( ', ' + Column2)
  FROM #test1 t2
  WHERE t1.Column1 = t2.Column1
  ORDER BY t1.Column1, t2.Column1
  FOR XML PATH('')
 ), 3, 1000)
FROM #test1 t1
GROUP BY Column1