datatable php codeigniter

    public function getdatatable()
    {
        $draw = intval($this->input->get("draw"));
        $start = intval($this->input->get("start"));
        $length = intval($this->input->get("length"));

        $query = $this->db->query("SELECT c.id as ID,d.name as Name,d.mobile_no as Num,f.title as Title,ct.name as City,c.call_time as Time FROM dairy d INNER JOIN calls c ON c.caller_id=d.id INNER JOIN feedback_type f ON f.id=c.feedback_text INNER JOIN city ct ON ct.id=c.city ORDER BY c.id DESC");
        $data = [];
        foreach($query->result() as $r) {
            $data[] = array(
                $r->ID,
                $r->Name,
                $r->Num,
                $r->Title,
                $r->City,
                $r->Time,
            );
        }

        $result = array(
            "draw" => $draw,
            "recordsTotal" => $query->num_rows(),
            "recordsFiltered" => $query->num_rows(),
            "data" => $data
        );
        return $result;
    }