Uncaught Error: Call to undefined method mysqli_stmt::get_result() [duplicate]

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• Call to undefined method mysqli_stmt::get_result 8 answers
• Can I mix MySQL APIs in PHP? 5 answers

Error: Uncaught Error: Call to undefined method mysqli_stmt::get_result()

How to use it right?

    public static function login($benutzername, $passwort){
        $result = Connection::getInstance()->db;
        $sql = 'SELECT * FROM users WHERE benutzername = ? AND passwort = ?';
        $stmt = $result->prepare($sql);
        $passwort = md5($passwort);

maybe use mysqli-stmt.bind-result ?

        $stmt->bind_param('ss', $benutzername, $passwort);
        $stmt->execute();
        $result = $stmt->get_result();

or mysqli_stmt_fetch?

        if ($result->num_rows != '0') {}

Thanks a lot!