[mamorunl]

1. You cannot use the $row variable outside your loop
2. Why use a loop? If it is only a username, there should only be 1 match, so you can just use

Код:

$row = mysql_fetch_array($query);

I don't know what mysql_fetch_assoc does, but I am going to check that now because I have a test the day after tomorrow (mysql_fetch_assoc looks like mysql_fetch_array.. oh well.)

As for the rest, it looks all OK to me.

I did it like this:

Код:

$query = mysql_query("SELECT * FROM users WHERE username='$_POST[username]'");
if(mysql_num_rows($query) == 0)
{
  // no results
  die('Username not found');
} else {
  $fetch = mysql_fetch_array($query);
  if(md5($_POST['password'] === $fetch['password'])) 
  {
    // a result and log the user in by means of a session
    $_SESSION['username'] == $_POST['username'];
  } else {
    die('Wrong password');
  }
}

Code is only for educational purposes only. It should not be considered as working, even though it most probably will.

-Edit: Ah, so that is mysql_fetch_assoc(); Just looked it up