USE arwiki_p; #set the language/project database

SET @course = 64; #set the course id based on Special:Courses

​

SELECT  c.course_id,u.user_name,

        SUM(CAST(r.rev_len as signed) - CAST(COALESCE(p.rev_len,0) as signed)) AS bytes_added,

        COUNT(r.rev_id) AS edit_count

    FROM ep_courses c

        LEFT JOIN user u

            ON u.user_id = if(instr(c.course_students,concat(":",u.user_id,";"))>0,u.user_id,c.course_students)

            AND u.user_id > 1000 #to weed out the registration numbers

        LEFT JOIN ep_articles a

            ON a.article_user_id = u.user_id

            AND a.article_course_id IN (@course)

        LEFT JOIN revision r

            ON r.rev_page = a.article_page_id

            AND r.rev_timestamp >= c.course_start

            AND r.rev_timestamp <= c.course_end

        LEFT JOIN revision p

            ON r.rev_parent_id = p.rev_id

WHERE c.course_id IN (@course)

GROUP BY user_name

ORDER BY course_id, bytes_added DESC;