HTML Faça uma mesa com dois cabeçalhos superiores
<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>
Radu Cuziac