Как работает fetch_row в CodeIgniter?

$query = "
  SELECT autor, title 
  FROM dle_post 
  WHERE autor ='' 
  AND UNIX_TIMESTAMP(date)>UNIX_TIMESTAMP('$from') 
  AND UNIX_TIMESTAMP(date)<UNIX_TIMESTAMP('$till')
";
$headings = array('Автор', 'Название', 'Размер');

if ($result = mysql_query($query) or die(mysql_error())) {  
    $objPHPExcel = new PHPExcel(); 
    $objPHPExcel->getActiveSheet()->setTitle('Список загруженных файлов'); 
    $rowNumber = 1; 
    $col = 'A'; 
    foreach($headings as $heading) { 
       $objPHPExcel->getActiveSheet()->setCellValue($col.$rowNumber,$heading); 
       $col++; 
    } 

    // Loop through the result set 
    $rowNumber = 2; 
    while ($row = mysql_fetch_row($result)) { 
       $col = 'A'; 
       foreach($row as $cell) { 
          $objPHPExcel->getActiveSheet()->setCellValue($col.$rowNumber,$cell); 
          $col++; 
       } 
       $rowNumber++; 
    } 

    // Freeze pane so that the heading line won't scroll 
    $objPHPExcel->getActiveSheet()->freezePane('A2'); 

    // Save as an Excel BIFF (xls) file 
    $objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, 'Excel5'); 

   header('Content-Type: application/vnd.ms-excel'); 
   header('Content-Disposition: attachment;filename="userList.xls"'); 
   header('Cache-Control: max-age=0'); 

   $objWriter->save('php://output'); 
   exit(); 
}