CakeSlow

  $conditons = array();


        if (empty($status)) {
            $status = 'NULL';
        }
        if (empty($from)) {
            $from = 'NULL';
        }
        if (empty($to)) {
            $to = 'NULL';
        }

        $conditons = array('AND' =>
            array(
                array('OR' => array(
                        array('ShipmentHistory.ship_from_date >=' => $from),
                        array($from . ' IS NULL')
                    )),
                array('OR' => array(
                        array('ShipmentHistory.ship_from_date <=' => $to),
                        array($to . ' IS NULL')
                    )),
                array('OR' => array(
                        array('ShipmentHistory.shipment_status_id' => $status),
                        array($status . ' IS NULL')
                    )),
            ),
            array(
                'ShipmentHistory.customer_id' => $cid
        ));