View fields from the same database column
I finally found the answer. 



  $data['uc_orders']['data2'] = array(
    'group' => t('Order') . ':data',
    'title' => t('Arrival Date'),
    'real field' => 'data',
    'help' => t('Arrival date choosen by customer during checkout.'),
    'field' => array(
    'handler' =>'uc_order_handler_field_arrive_date',
      'click sortable' => TRUE,
     ),
     'sort' => array(
       'handler' => 'views_handler_sort',
     ),
     'filter' => array(
       'handler' => 'views_handler_filter_string',
     ),
  );

  $data['uc_orders']['data'] = array(
    'group' => t('Order') . ':data',
    'title' => t('Ship Date'),
    'help' => t('The date to ship the order.'),
    'field' => array(
    'handler' =>'uc_order_handler_field_ship_date',
      'click sortable' => TRUE,
     ),
     'sort' => array(
       'handler' => 'views_handler_sort',
     ),
     'filter' => array(
       'handler' => 'views_handler_filter_string',
     ),
  );



The solution is to add 'real field' =&gt; 'field name', and change the $data id.