$sql = "SELECT dr_gorod, dr_udal, dr_kolmag FROM dr_goroda";  
$res = mysql_query($sql) or die ( "Error in $sql : ". mysql_error()); 
if(mysql_num_rows($res) > 0) 
{ 
  header('Content-Type: application/vnd.ms-excel; name="table.csv"'); 
  header('Content-Disposition: attachment; filename="table.csv"'); 
  echo "dr_gorod;dr_udal;dr_kolmag".   "\r\n";
  while(($row = mysql_fetch_assoc($res)) !== false) 
  { 
    foreach($row as $column => $val) 
    { 
        $val = '"'.str_replace('"', '""', $val).'"';  // для строк 
        $row[$column] = $val; 
    } 
    $row = implode(';', $row); 
    echo($row."\r\n"); 
  } 
}