Конференц-залы в Маньковка

SELECT DISTINCT a.id_cat, a.on_main, a.name_cat, a.comment_cat, a.link_cat, a.dt_begin FROM catalog AS a LEFT JOIN category_relation AS b ON (a.id_cat=b.id_obj) WHERE a.type_cat='object' AND a.visibility_cat='1' AND a.dt_begin < '2019-08-21 21' AND a.dt_end > '2019-08-21 21' AND a.rn_id=51 ORDER BY a.dt_begin DESC LIMIT 300