How to get the counted values with a comma separator as a single row value

Question

Using the following query I getting the result like how much the players in the table, but now I also want which players are in the same table, and show those players id with a

Answer 1

The function you are looking for is GROUP_CONCAT. See the documentation:

http://dev.mysql.com/doc/refman/5.7/en/group-by-functions.html#function_group-concat

In your example you can just create one more subquery (example below). Or JOIN it in a standard way to the original query.

...
(
      SELECT GROUP_CONCAT(gtp.id)
          FROM game_table_players gtp
          LEFT JOIN game_rounds gr ON gr.id = gtp.game_round_id
      WHERE gt.id = gtp.game_table_id
          AND gtp.quit<>1 AND gr.finish=0
) AS players,
...

Note the comment on NULL handling in GROUP_CONCAT. If you want to show zeros when there aren't any players present, you might want to use COALESCE(GROUP_CONCAT(gtp.id), 0) instead.