Outputting incorrect username or password - php

Question

I need help with this code to output incorrect username or password but it doesn't :(
<?php
include 'functions.php';
if(loggedin()){
header("Location: index.php");
exit();
}
if(isset($_POST['login'])){
$username=$_POST['Username'];
$password=$_POST['Password'];
if(isset($_POST['rememberme'])){
$rememberme = $_POST['rememberme'];
}
if($username&&$password){
$login = mysql_query("SELECT * FROM php_customer WHERE Username='$username'");
while($row = mysql_fetch_assoc($login)){
$db_password = $row['Password'];
if($password == $db_password){
$loginok= TRUE;
}
else{
$loginok= FALSE;
}
if($loginok==TRUE)
{
if($rememberme=="on"){
setcookie('Username',$username, time() + 7200);
}else if ($rememberme==""){
$_SESSION['Username'] = $username;}
header("Location: index.php");
exit();
}
echo "Incorrect Username or Password";
}
}
}
?>
I've tried adding it by the $loginok=false; but nothing works. I don't want you guys to go psycho on me, this is a 1 line of code kinda thing. Also yes I know you can log in if you store a username as a cookie. Just trying to validate atm.

Answer 1

Set your flag to false at the very beginning, before doing the SQL query:
$loginok = FALSE;
$login = mysql_query(....);
Why? Because the SQL query won't return anything for a username that doesn't exist in the table, obviously.
Which means, also, you need to make sure that the line echo "Incorrect Username or Password"; and the if-statement based on $loginok are not inside the loop which goes through the recordset, but after it. Which means you need to learn how to properly indent code so its clear where if-statements and loops begin and end.