cara membuat login level dengan php

if(isset($_POST["submit_login"])) { $username = $_POST["username"]; $password = $_POST["password"]; $sql_login = mysqli_query($koneksi, "SELECT * FROM akun WHERE username = '$username' AND password = '$password'"); if(mysqli_num_rows($sql_login)0) { $row_akun = mysqli_fetch_array($sql_login); $_SESSION["akun_id"] = $row_akun["id"]; $_SESSION . simak umi login