问还有其他强SQL注入来保护数据吗？

EN

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);

  $email=$conn->real_escape_string(trim($_POST['email']));
  $subject=$conn->real_escape_string(trim($_POST['subject']));
  $mobileno=$conn->real_escape_string(trim($_POST['contact']));

// prepare and bind
  $sql="INSERT INTO creatcontact (email, subject, mobileno) VALUES (?,?,?)";
  $stmt = $conn->prepare($sql);
  $stmt->bind_param("ssi",$email, $subject, $mobileno);
  $stmt->execute();
//redirect code
 header('Location: index.php');
  $stmt->close();
  $conn->close();