How to display room type in room type column(php table)?

<?php
  $servername = "localhost";
  $username = "root";
  $password = "";
  $database = "safarihostel";
  $conn = mysqli_connect($servername, $username, $password, $database);

if (isset($_POST['addroom'])) {
    $rt = $_POST['rtype'];
    $rn = $_POST['rno'];
    $rr = $_POST['rrate'];
    $mp = $_POST['maxp'];

    mysqli_query($conn, "INSERT INTO `rooms`(`room_type`, `room_rate`, `room_no`, `max_person`) VALUES ('$rt','$rr','$rn','$mp')");
}
?>

<!DOCTYPE html>
<html>
<body>
    <table class="table table-bordered table-striped mb-none" id="datatable">
        <thead>
          <tr>
              <th>Room Type</th>
              <th>Room Rate</th>
              <th>Room No.</th>
              <th>Max Person</th>
          </tr>
        </thead>
        <tbody>
    <?php
$sql = "SELECT * FROM rooms";
  if ($result = mysqli_query($conn, $sql)) {
    if (mysqli_num_rows($result) > 0) {
    while ($row = mysqli_fetch_array($result)) {?>
    <tr>
          <td><?php echo $row['room_type']; ?></td>
          <td><?php echo $row['room_rate']; ?></td>
          <td><?php echo $row['room_no']; ?></td>
          <td><?php echo $row['max_person']; ?></td>

        </tr>
     <?php }
   }
 }
 ?>
        </tbody>
    </table>

                <div class="modal fade" id="add">
  <div class="modal-dialog">
    <div class="modal-content">

      <form method="POST" action="" role="form" id="addroom">

      <div class="modal-header">
        <button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">&times;</span></button>
        <h4 class="modal-title">Add Room</h4>
      </div>

      <div class="modal-body" style="color: black;">
        <p><label> Room Type: </label>
              <select class="input-sm" name="rtype" id="rtype" onchange="rooms()" required>
                <option></option>
                <?php
                  $roomtype = "SELECT * FROM roomtypes";
                  $roomresult = mysqli_query($conn, $roomtype);
                  while ($row = mysqli_fetch_array($roomresult)) {?>
                    <option value="<?php echo $row[2]; ?>"><?php echo $row[1];?> </option>
                 <?php }
                ?>
              </select></p>

         <p><label> Room Rate: </label>
              <input type="text" class="input-sm" name="rrate" id="rrate" required></p>

        <p><label> Room No.: </label>
                <input type="text" class="input-sm" name="rno" id="rno" required></p>

        <p><label>Max Person: </label>
                  <input type="text" class="input-sm" name="maxp" value="" onkeypress="return isNumberKey(event)" required></p>

      </div>

      <div class="modal-footer">
        <button type="submit" class="btn btn-primary" name="addroom">SAVE</button>
      </div>

    </form>
    <div class="clearfix"></div>
    </div><!-- /.modal-content -->
  </div><!-- /.modal-dialog -->
</div><!-- /.modal -->

<script>
  (function() {
    document.getElementById('rtype').onclick = function () {
        rrate.value = rtype.value;
        }
    }());
</script>
</body>
</html>