function overzicht_verkopen($bedr_id)
  {
      $query = '
      SELECT
        order_kenmerk.order_id,
        order_kenmerk.opdr_nr_concept,
        order_kenmerk.datum_retour,
        order_kenmerk.order_status,
        SUM(orderregel.prijs * orderregel.aantal) AS order_prijs,
        SUM(orderregel.prijs * orderregel.co_factor * orderregel.aantal) AS concept_prijs,
        SUM(orderregel.prijs * orderregel.de_factor * orderregel.aantal) AS dealer_prijs,
        SUM(orderregel.totaal_inkoop) AS order_inkoop,
        COUNT(factuur.order_id) AS aantal_facturen
      FROM
        orderregel, order_kenmerk  LEFT JOIN factuur
      ON
        order_kenmerk.order_id = factuur.order_id
      WHERE
        order_kenmerk.order_id = orderregel.order_id
      AND
        order_kenmerk.opdr_nr_concept <> ""
      AND
        order_kenmerk.bedr_id = '.$bedr_id.'
      GROUP BY
        order_kenmerk.order_id
      ORDER BY
        order_kenmerk.opdr_nr_concept';
        
      return $this->db->query($query);
  }