comment input in php

<?php
session_start();

// initializing variables

$email    = "";
$comment = "";
$errors = array(); 

// connect to the database
$db = mysqli_connect('localhost', 'root', '', 'login');

if (isset($_POST['submit'])) {

  $email = mysqli_real_escape_string($db, $_POST['email']);
  $comment = mysqli_real_escape_string($db, $_POST['comment']);
  
  
  // form validation: ensure that the form is correctly filled ...
  // by adding (array_push()) corresponding error unto $errors array
  
  if (empty($email)) { array_push($errors, "Email is required"); }
  if (empty($comment)) { array_push($errors, "comment is required"); }
  

  if (count($errors) == 0) {
    $query = "INSERT INTO coment (email, comment) 
          VALUES('$email','$comment')";
    mysqli_query($db, $query);


    $_SESSION['email'] = $email;
    $_SESSION['comment'] = $comment;
    $_SESSION['success'] = "Your message is received";
    header('location: contactus.php');
  }

}
?>