Código PHP:
if ($estado=" ")
$sql = mysql_query("SELECT * FROM phpbb_users ORDER BY user_id") or die (mysql_error());
else
$sql = mysql_query("SELECT * FROM phpbb_users WHERE user_from = '$estado' ORDER BY user_id") or die (mysql_error());
while ($row = mysql_fetch_array($sql)) {
$id = "$row[user_id]";
$nick = "$row[username]";
$gamertag = "$row[user_xbl]";
if($gamertag){
echo"<tr><td><a href='http://www.gamerzone.com.mx/perfilusuario/$id/' target='_self'>$nick</a></td><td><strong>$gamertag</strong></td></tr>";
} else { } }