SET max_recursive_iterations = 3;

WITH RECURSIVE deepcat (subcat) AS

(

  SELECT 'Stub-Class_articles'

​

  UNION DISTINCT

​

  SELECT page_title

  FROM categorylinks

  JOIN page ON page_id = cl_from AND page_namespace = 14

  JOIN deepcat ON cl_to = subcat

)

SELECT page_namespace, COUNT(DISTINCT page_title)

FROM page

JOIN categorylinks ON cl_from = page_id

JOIN deepcat ON cl_to = subcat

GROUP BY page_namespace;