php - Send mail to mailinglist based on variables

one text

I have a simple query that shows specific people in a table. I want to create a 'mailto'-button underneath the table with the mail-adresses specified in a column. I tried putting the array straight into to 'a href', but this doesn't seem to work.

      <table>
        <tr>
          <td>id</td>
          <td>Name</td>
          <td>Email</td>
        </tr>

        <?php
          $records = mysqli_query($conn,"SELECT * FROM regkamp WHERE kampnaam='$kampnaam'");
          while($data = mysqli_fetch_array($records)) {
            ?>
            <tr>
              <td><?php echo $data['id']; ?></td>
              <td><?php echo $data['name']; ?></td> 
              <td><?php echo $data['email']; ?></td> 
            </tr>   
          <?php } ?>
        </table>

        <button>
          <a href="mailto:<?php echo $data['email']; ?>?SUBJECTSkaykamp">mail-list</a>
        </button>