Código PHP:
<table width="200" border="1">
<tr>
<td>operador</td>
<td>tot. mts. </td>
</tr>
<tr>
<td>
<?php
include("conn.php");
$link=Conectarse();
$q1=mysql_query("SELECT DISTINCT oper_prin FROM `principal`");
while($row = mysql_fetch_array($q1))
echo " <tr><td>".$row["oper_prin"]."</td>" ;
mysql_free_result($q1);
?></td>
</tr>
<td> </td>
<td> </td>
</tr>
</table>