<?php
    session_start();

    mysql_connect('localhost','test','Asd!');
    mysql_select_db('test');

    if (isset($_POST['username']) && isset($_POST['password'])) {
        $result = mysql_query("SELECT level FROM users WHERE username='" . mysql_real_escape_string($_POST['username']) . "' AND password='" . md5($_POST['password']) . "'");
        if (mysql_num_rows($result) == 1) {
            $data = mysql_fetch_row($result);
            $_SESSION['username'] = $_POST['username'];
            $_SESSION['level'] = $data[0];
        }
    }

    mysql_close();
?>