SELECT
a.idarticle as a_id,
a.title as a_title,
a.seo_url as a_url,
a.short_lead as a_short_lead,
a.date_publication as a_date_publication,
a.flag_has_video as a_has_video,
ac.idcategory as idcat,
c.name AS c_name,
c.url as c_url,
c.idcategory as category_id
FROM article a
LEFT JOIN article_category ac ON a.idarticle=ac.idarticle
LEFT JOIN category c ON ac.idcategory=c.idcategory
WHERE c.idparent='' and a.date_publication