I have set-up a MySQL database called test_db with table authorised_users.
user_name varchar(35)
user_id varchar(16)
user_password varchar(16)
account varchar(8)
access_code varchar(8)

When executing MySQL line command
SELECT access_code FROM authorised_users
WHERE user_id = 'MagooW' AND user_password = 'qwerty' AND account = '46815185';
+-------------+
| access_code |
+-------------+
86190185 as expected

executing PHP MySQL

$query = "SELECT accesscode INTO $access FROM authorised_users WHERE
(user_id = $userid AND user_password = $password AND account = $account)";
$result = $db->query($query);
$db->close();
echo ('$access after SELECT = ' .
$access " . <BR><BR>");

nothing appears to be returned ($access)
Session userid = MagooW
Session password = qwerty
Session account = 46815185
Session accesscode = 86190185

$userid = MagooW
$password = qwerty
$account = 46815185
$accesscode = 86190185

$access after SELECT = 0