use wikidatawiki_p;

select cast(coalesce(x.ips_site_page, z.ips_site_page) as char) coal, y.ips_item_id, y.cnt

from (select ips_item_id, count(*) cnt from wb_items_per_site group by ips_item_id) y 

left join wb_items_per_site x on x.ips_item_id = y.ips_item_id and x.ips_site_id = 'ruwiki' 

left join wb_items_per_site z on z.ips_item_id = y.ips_item_id and z.ips_site_id = 'enwiki'

order by y.cnt desc

limit 100;