Number of articles in a category 

USE knwiki_p;

SELECT page_id, page_title, page_is_new,page_latest, page_len, page_is_redirect,page_namespace,    page_restrictions,    page_counter, page_touched, page_links_updated,    page_no_title_convert    

FROM page AS p2 WHERE p2.page_namespace = 0 AND p2.page_title

IN (SELECT page_title

    FROM page

    WHERE page_id

    IN (SELECT cl_from

        FROM categorylinks

        WHERE cl_to = "WikiProject Pharmacology articles "));

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