*********this is my scripts,

   <?php
    if(isset($_POST['submit']))
    {
        $username   = $_POST['username'];
        $password   = md5($_POST['password']);
        $date_login  = date("y-m-d");
        $level = $row['level_id'];
        $status = $row['status'];
        $acc_status = $row['acc_status'];


    if($level == "1" && $status == "1"){
    $query = mysql_query("SELECT * FROM professor WHERE username='$username' AND password='$password'");
    $cek = mysql_num_rows($query);
    $row = mysql_fetch_array($query);
    $prof = $row['prof_id'];

    if ($cek) {
    $_SESSION['username'] = $username;
    $_SESSION['prof_id'] = $prof;
    $_SESSION['level_id'] = $level;
    $_SESSION['status'] = $status;

    header("location: user/home_prof.php");
    $save = mysql_query("update professor set date_login = '$date_login' where
    username = '$username'");
    }
    else {
    $error = "Failed Login";
    }
    }

    if($level == "2" && $status == "1" && $acc_status == "0"){
    $query = mysql_query("SELECT * FROM student WHERE username='$username' AND password='$password'");
    $cek = mysql_num_rows($query);
    $row = mysql_fetch_array($query);
    $student = $row['student_id'];

    if ($cek) {
    $_SESSION['username'] = $username;
    $_SESSION['student_id'] = $student;
    $_SESSION['level_id'] = $level;
    $_SESSION['status'] = $status;
    $_SESSION['acc_status'] = $acc_status;

    header("location: user/home_student.php");
    $save = mysql_query("update student set date_login = '$date_login' where username = '$username'");
    }
    else {

    }
    }
    }
    ?>