Filtering on multiple categories

EE Cat Filtering

SELECT count( cp.entry_id ) AS total_items, 
cp.cat_id, 
c.cat_name as category_name, 
c.cat_url_title as category_url_title
FROM exp_weblog_titles AS wt
    INNER JOIN exp_category_posts AS cp ON wt.entry_id = cp.entry_id
        INNER JOIN exp_categories AS c ON cp.cat_id = c.cat_id
        INNER JOIN exp_category_posts AS cp2 ON wt.entry_id = cp2.entry_id
     INNER JOIN exp_categories AS c2 ON cp2.cat_id = c2.cat_id
WHERE wt.weblog_id = 57 
AND wt.status != 'closed'
AND c.site_id = 8 AND c2.site_id = 8
AND c.group_id = 40 AND c2.cat_id = {segment_2_category_id}
GROUP BY c.cat_name