<?PHP

  $rand = 1000;
  for($i=1;$i<=$count[0]['count'];$i++)
  {
    do
    {
      // generate id
      $record['cart_order_id'] = date("ymd-His-").$rand;
    }
    // check 1. id is not in db   2. id is not already generated
    while ( array_search($record,$existing_id) !== FALSE ||
            array_search($record['cart_order_id'],$used) !== FALSE );
    // store id
    $used[] = $record['cart_order_id'];
    // increment counter
    $rand = ($rand < 9999) ? $rand+1 : '1000';
  }
  // output results
  echo "id\r\n".implode("\r\n",$used);

?>