Статьи в нескольких категориях

public function getArticlesCount($only_published=true) {
        $articles = array();
	$today    = date("Y-m-d H:i:s");
        if ($only_published){
            $this->where("con.published = 1 AND con.pubdate <= '$today'
                      AND (con.is_end=0 OR (con.is_end=1 AND con.enddate >= '$today'))");
        }
        $sql = "SELECT 1
                FROM cms_content con
                WHERE con.is_arhive = 0
                      {$this->where}
                {$this->group_by}
                {$this->order_by}\n";
        $result = $this->inDB->query($sql);
        return $this->inDB->num_rows($result);
    }

        $sql = "SELECT con.*, 
                       con.pubdate as fpubdate,
                       u.nickname as author,
                       u.login as user_login
                FROM cms_content con
				LEFT JOIN cms_users u ON u.id = con.user_id
                WHERE con.category_id = '$category_id' AND con.published = 1 AND con.is_arhive = 0 AND con.pubdate <= '$today'
                      AND (con.is_end=0 OR (con.is_end=1 AND con.enddate >= '$today'))
                ORDER BY con.".$orderby." ".$orderto."
                LIMIT ".(($page-1)*$perpage).", $perpage";

$sql = "SELECT  
            con.*,  
            con.pubdate AS fpubdate, 
            u.nickname AS author, 
            u.login AS user_login 
        FROM 
            cms_content con 
        LEFT JOIN cms_content_cats cat 
            ON con.id = cat.item_id 
        LEFT JOIN cms_users u 
            ON con.user_id = u.id 
        WHERE 
            con.published = 1 
            AND con.is_arhive = 0 
            AND (con.is_end=0 OR (con.is_end=1 AND con.enddate >= '$today' AND con.pubdate <= '$today')) 
            AND (con.category_id=$category_id OR cat.category_id =$category_id) 
        GROUP BY con.id 
        ORDER BY con.".$orderby." ".$orderto."
        LIMIT ".(($page-1)*$perpage).", $perpage";

 LEFT JOIN cms_content_cats cat 
        ON con.id = cat.item_id 

    public function whereCatIs($category_id) {
        $this->where("con.category_id = {$category_id} OR cat.category_id = {$category_id}");
    }