Here's an interesting way of contencating values in one column. It makes use of the new XML capabilities.

use master


select column_name as col1 FROM INFORMATION_SCHEMA.Columns
WHERE table_name = 'spt_values'


select (select column_name as col1 FROM INFORMATION_SCHEMA.Columns
WHERE table_name = 'spt_values' for xml raw, elements, type).query('
                                              for $col1 in (row/col1)
                                              return concat($col1, ",")')

Order can be forced by using

       'for $col1 in (row/col1)
        order by $col1 ascending
        return concat($col1, ",")'

For descending order change ascending to descending.