Where clause not working with aes_decrypt function

[Brannon Glover]

I am trying to validate a user's login by using the aes_decrypt function, but it isn't working properly for me. I am echoing the results to the screen and everything appears correct, but it still won't let me into the site. Thanks for any help.

$loginUser = "SELECT username, aes_decrypt(password, 'key')
FROM login
WHERE username = '$username' and password = aes_decrypt('$password', 'key')";
$userIn = mysql_query($loginUser) or die("The login error is: " . mysql_error());