WITH subcats(sc_title, sc_name) AS

(

  SELECT page_title, REGEXP_REPLACE(page_title, '^Compositions_by_', '')

  FROM categorylinks

  JOIN page ON page_id = cl_from

  WHERE cl_to = 'Compositions_by_composer'

    AND page_namespace = 14

    AND page_title LIKE 'Compositions\_by\_%'

)

SELECT CONCAT('[[Template:', sc_name, ']]') AS template,

       CONCAT('[[:Category:', sc_title, ']]') AS subcategory,

       COUNT(*)

FROM subcats

JOIN categorylinks ON cl_to = sc_title

LEFT JOIN page ON page_namespace = 10 AND page_title = sc_name

WHERE page_id IS NULL

GROUP BY sc_title

HAVING COUNT(*) >= 2;