PHP: PHP3 Authentication using MySQL

PHP3 Authentication using MySQL (also has nice query_db() function
to return an array of arrays from a MySQL query result).

<?
// All of this SHOULD go into an .inc file

function query_db($query) {
    // connect and get row(s)
    $mysql = mysql_pconnect('host', 'sqluser', 'sqlpass');
    $success = mysql_select_db('database');
    $result = mysql_query($query, $mysql);

    if ($err) {
        // return empty array :P
        echo "Error querying database<BR>\n";
        echo "$err<BR>\n";
        echo "Please alert <A HREF=\"root@yoursite.com\">admin</A><BR>\n";
        return array();
    } else {
        // make the array
        $ret_array = array();

        // do we have something?
        if (mysql_num_rows($result) > 0) {

            // yes get each one and stuff it in
            while ($row = mysql_fetch_array($result)) {
                $ret_array[] = $row;
            }
        }

        // returns arrays of rows, or array() if no rows
        return $ret_array;
    }
}

function authenticate() {
    // not authenticated, or previously failed authentication
    Header('WWW-authenticate: basic realm="Realm name");
    Header('HTTP/1.0 410 Unauthorized');
    echo "You must have a valid login and password to access this page\n";
}

function LoginIsValid($uname, $passwd) {
    // don't even bother if they're empty
    if ($uname == "" | $passwd == "")
        return 0;
        // query the database
    $query = "SELECT userid,password FROM users WHERE username='$uname'";
    $result = query_db($query);
        // did we get anything back
    if (count($result) != 0) {
        // let's get 'each one' (just for showing how to get multiple rows w/ my query_db)
        while (list($key, $arr) = each($result)) {
            $row = $arr;            // get a row
            $uid = $row['userid'];
            $pass = $row['password'];
            if ( (crypt($passwd, $pass) == $pass) and ($pass != "") ) {
                return $uid;    // valid login
            } else {
                return 0;    // invalid login
            }
        }    // end while()
    } else {
        return 0;            // not even a user by that name!
    }    // end if (count($result) != 0)
}    // end function

?>

<?
    // THIS part goes in your page
    require('db.inc');     // or where ever you have the above code
    if (LoginIsValid($PHP_AUTH_USER,$PHP_AUTH_PW) == 0)
        authenticate();
    // if I need an else or the like, let me know!
?>