use huwiki_p;

​

SELECT

    CONCAT(SUBSTR(user_registration, 1, 4), 'q', (SUBSTR(user_registration, 5, 2) - 1) DIV 3 + 1) AS registration_date,

    -- SUBSTR(user_registration, 1, 6) AS registration_date,

    count(*) AS new_users

FROM (

    SELECT

        user_id,

        user_registration,

        count(*) AS recent_edits

    FROM

        user

        JOIN actor ON user_id = actor_user

        JOIN recentchanges ON actor_id = rc_actor AND rc_timestamp > DATE_FORMAT(NOW() -INTERVAL 30 DAY, '%Y%m%d%H%i%s')

    GROUP BY user_id, user_registration

    HAVING recent_edits >= 5

) tmp

GROUP BY registration_date

ORDER BY registration_date

;