<table class="table table-striped table-bordered table-hover dataTables-example" >
  <thead>
    <tr>
      <th>Nama Murid</th>
      <th>Nilai</th>
    </tr>
  </thead>
  <tbody>
    <?php $no=1; ?>
    <?php foreach ($murid as $row_murid) { ?>
      <tr class="gradeX">
        <td ><?php echo $row_murid['nama_murid']; ?></td>
        <?php foreach ($nilai as $row_nilai) { ?>
          <?php /* disini dicek dulu apakah $row_nilai['id_murid'] == $row_murid['id'], kalau sama baru tampilkan nilai */ ?>
          <td><?php echo $row_nilai['nilai']; ?></td>
        <?php } ?>
      </tr>
    <?php } ?>
  </tbody>
</table>