Need help with a prepared statement to log a user in

[Jfunch]

I'm trying to convert my code for querying and accessing user login info and putting into session varibles to using a prepared statement to do the same thing, but I can't figure it out.

Original:

$query = "SELECT id FROM customer WHERE username='$username' AND password='$password' LIMIT 1";
$result = $db_obj->query($query);
if($db_obj->error) exit ($db_obj->error);

$login_check = $result->num_rows;

if($login_check == 1){
 while($row = $result->fetch_array(MYSQLI_ASSOC)){ 
        // Get member ID into a session variable
        $id = $row["id"]; 
	}
        $_SESSION['id'] = $id;
        // Get member username into a session variable
	       
        $_SESSION['username'] = $username;
       
        // Print success message here if all went well then exit the script
		//header("location: index.php?id=$id"); 
		header("location: index.php");
		exit();
     // close while
} else {
// Print login failure message to the user and link them back to your login page
  print '<br /><br /><font color="#FF0000">No match in our records, try again </font><br />
<br /><a href="user_login.php">Click here</a> to go back to the login page.';
  exit();
}

Code trying to use prepared statement:

$stmt = $db_obj->stmt_init(); 
if($stmt->prepare("SELECT `id`FROM `customer` WHERE `username` = ? AND pass = ? LIMIT 1")) { 
$stmt->bind_param($username, $password); 
$stmt->execute(); 
$stmt->bind_result($username, $password);
 
if ($stmt->fetch()){ 
    while($row = $result->fetch_array(MYSQLI_ASSOC)){ 
        // Get member ID into a session variable
        $id = $row["id"]; 
	}
        $_SESSION['id'] = $id;
        // Get member username into a session variable
	       
        $_SESSION['username'] = $username;
       
        // Print success message here if all went well then exit the script
		//header("location: index.php?id=$id"); 
		header("location: index.php");
		exit();
     // close while
} else {
// Print login failure message to the user and link them back to your login page
  print '<br /><br /><font color="#FF0000">No match in our records, try again </font><br />
<br /><a href="user_login.php">Click here</a> to go back to the login page.';
  exit();
}

I believe my problem is in the while loop and with trying to use fetch(), but I'm not sure how to go about doing it. If someone could help I would appreciate it. Thank you.

[hag++]

Check the manual for the bind_param method. The first arg needs to be a format string specifying what type(s) of parameters you are passing.

For example, if both username and password are strings you would use:

$stmt->bind_param("ss", $username, $password);