问在php中为文件名设置表的列名

EN

    <?php
$con = mysqli_connect("127.0.0.1","root","","dbname");
if (mysqli_connect_errno())
  {
  echo "Failed to connect to MySQL: " . mysqli_connect_error();
  }
session_start();
$id=$_GET['id'];
$sql='
SELECT Name_of_company 
  FROM companyinformation 
 WHERE id="$id"
';
$result=mysqli_query($con,$sql);
$rows=mysqli_fetch_array($result);
echo $sql;


$createfile=$rows.".txt";

$email=$_SESSION['coll'];
$rnumber=$_SESSION['roll_number'];
$rollnumber="Roll Number \n";
$Email="Email Address ";
$newline="\n";
$rollema=$Email.$rollnumber;

$myfile = fopen($createfile, "a") or die("Unable to open file!");
fwrite($myfile, $email);
fwrite($myfile," ");
fwrite($myfile, $rnumber);
fwrite($myfile, $newline);
fclose($myfile);
//echo "<script>alert('Register Successfully');window.open('studentloginpage.php','_self');</script>";
?>