tente algo assim
// note we need to order by maincategory for this to work
//
$query = "SELECT DISTINCT a.categoryname AS maincategory, b.categoryname AS
smallcategory FROM wscategories a, wssubcategories b WHERE a.SECTION = 'girls' AND
b.parentcategory = a.id
ORDER BY maincategory ASC,
smallcategory ASC
";
$result = mysql_query($query) or die(mysql_error());
// keep track of previous maincategory
$previous_maincategory = NULL;
while ($row = mysql_fetch_assoc($result))
{
// if maincategory has changed from previouscategory then display it
if ($previous_maincategory != $row['maincategory']) {
echo $row['maincategory'];
}
echo "<br/>";
echo $row['smallcategory'];
echo "<br/>";
// record what the previous category was
$previous_maincategory = $row['maincategory'];
}