use tewiki_p;

​

SELECT NQ.title, COUNT(1) AS page_contributors

FROM

(

      JOIN tewiki_p.page P ON R.rev_page=P.page_id

      JOIN rewiki_p.actor A ON R.rev_actor=A.actor_id

    WHERE R.rev_timestamp > 20191201000000

      AND R.rev_timestamp < 20200101000000

      AND P.page_namespace = 0

    GROUP BY A.actor_name, P.page_title

    ORDER BY edits DESC

) AS NQ

GROUP BY title

ORDER BY page_contributors DESC

LIMIT 20