Код: Выделить всё
$this->db->select('*, news.id as news_id, news.created as created_on, CONCAT(users.firstname, users.surname) as article_author, CONCAT(modified_user.firstname, modified_user.surname) as modified_author');
$this->db->join('users', 'users.id = news.author', 'left');
$this->db->join('users modified_user', 'modified_user.id = news.modified_by', 'left');
Подробнее здесь: https://stackoverflow.com/questions/642 ... iter-query