SELECT actor_name, count(*) AS uploads

FROM commonswiki_p.page p 

INNER JOIN commonswiki_p.categorylinks cl ON p.page_id = cl.cl_from 

INNER JOIN commonswiki_p.revision r ON p.page_id = r.rev_page

join actor on rev_actor = actor_id and actor_user is not null

WHERE cl.cl_to IN (

  "Images_from_Wiki_Loves_Monuments_2018_in_Latvia"

 ,"Images_from_Wiki_Loves_Monuments_2017_in_Latvia"

 ,"Images_from_Wiki_Loves_Monuments_2016_in_Latvia"

 ,"Images_from_Wiki_Loves_Monuments_2015_in_Latvia"

)

AND p.page_namespace = 6 

AND r.rev_parent_id = 0

GROUP BY actor_name

ORDER BY uploads DESC;