stmt native sebelum revisi

<?php

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



    $username = filter_input(INPUT_POST,'username',FILTER_SANITIZE_STRING);
    $password = filter_input(INPUT_POST,'password',FILTER_SANITIZE_STRING);

    $sql = "SELECT * FROM users WHERE username=:username";

    $query_param = array(":username" => $username);

    try {
      $stmt = $db->prepare($query);
      $result = $stmt->execute($query_params);
    } catch (Exception $error) {
      die("error query failed");
    }
    $row = $stmt->fetch();

    if ($row) {
      if (password_verify($password,$row['password'])) {
        session_start();
        $_SESSION['user'] = $row;
        header("Location: index.php");
      }
    }
  }


 ?>