text: SELECT CONCAT_WS(',', 'data', 'fuse', 'labs', '2021');
  SELECT CONCAT_WS(',', 'data', NULL, 'bend');
  SELECT CONCAT_WS(',', 'data', NULL, NULL, 'bend');
  SELECT CONCAT_WS(NULL, 'data', 'fuse', 'labs');
  SELECT CONCAT_WS(',', to_varchar(number), 'data', to_varchar(number+1)) from numbers(3) order by number;
  SELECT CONCAT_WS(NULL, to_varchar(number), 'data') from numbers(3);
  SELECT CONCAT_WS(',', NULL); -- is emtpy, not NULL
  