HTML

html table two headers

<table>
  <col>
  <colgroup span="2"></colgroup>
  <colgroup span="2"></colgroup>
  <tr>
    <th colspan="2" scope="colgroup">Mars</th>
    <th colspan="2" scope="colgroup">Venus</th>
  </tr>
  <tr>
    <th scope="col">Produced</th>
    <th scope="col">Sold</th>
    <th scope="col">Produced</th>
    <th scope="col">Sold</th>
  </tr>
</table>