ordering

<th>
                    NIS
                    <a href="index.php?sort=nis&order=asc">⬆</a>
                    <a href="index.php?sort=nis&order=desc">⬇</a>
                </th>
                <th>
                    Nama Lengkap
                    <a href="index.php?sort=nama_lengkap&order=asc">⬆</a>
                    <a href="index.php?sort=nama_lengkap&order=desc">⬇</a>
                </th>