Sample code

<?php foreach ($rows as $row_count => $row): ?>
<tr>
  <?php foreach ($row as $field => $content): ?>
    <?php if ($field=='first_field') : ?>
    <td>Column A</td>
    <?php elseif ($field=='second_field') : ?>
    <td>
      <table>
        <tr>
          <td>first column</td>
          <td>second column</td>
          <td>third column</td>
        </tr>
      </table>
    </td>
    <?php endif; ?>
  <?php endforeach; ?>
</tr>
<?php endforeach; ?>