if ( (!isset($HTTP_GET_VARS['sort'])) || (!ereg('[1-8][ad]', $HTTP_GET_VARS['sort'])) || (substr($HTTP_GET_VARS['sort'], 0, 1) > sizeof($column_list)) ) {
    for ($i=0, $n=sizeof($column_list); $i<$n; $i++) {
      if ($column_list[$i] == 'PRODUCT_LIST_NAME') {
        $HTTP_GET_VARS['sort'] = $i+1 . 'a';
        $order_str = ' order by pd.products_name';
        break;
      }