What would the IF condition be?

So I have toy'd with this a bit and I can't seem to get the proper if condition to only create the link if the results are something.

The code:

$addonid = $db->query_read ("
  SELECT drc.threadid AS threadid
  FROM `" . TABLE_PREFIX . "modsys_settings` AS drc
  LEFT JOIN `" . TABLE_PREFIX . "thread` AS thread
  ON(drc.mod_addons=" . $threadinfo['threadid'] . ")
  WHERE thread.threadid IN (" . $threadinfo['threadid'] . ")
");

$post['addons'] = '<ul>';

while ($addons = $db->fetch_array ($addonid)) {    
  $ci_counter = $db->query_read ("
    SELECT drc.mod_addons AS addon, drc.threadid, thread.threadid AS threadid, thread.title AS threadtitle
    FROM `" . TABLE_PREFIX . "modsys_settings` AS drc 
    LEFT JOIN `" . TABLE_PREFIX . "thread` AS thread ON(drc.mod_addons=" . $threadinfo['threadid'] . ") 
    WHERE thread.threadid IN (" . $addons['threadid'] . ")
  ");

  $counter = $db->fetch_array ($ci_counter);
  $post['addons'] .= 'TEST - <li><a href="showthread.php?t=' .   $addons['threadid'] . '">'. $counter['threadtitle'] .'</a></li>';
}

$post['addons'] .= '</ul>';

to me it seems like:

$addonid = $db->query_read ("
  SELECT drc.threadid AS threadid
  FROM `" . TABLE_PREFIX . "modsys_settings` AS drc
  LEFT JOIN `" . TABLE_PREFIX . "thread` AS thread
  ON(drc.mod_addons=" . $threadinfo['threadid'] . ")
  WHERE thread.threadid IN (" . $threadinfo['threadid'] . ")
");
if ($addons['threadid'] != '') {
  $post['addons'] = '<ul>';

  while ($addons = $db->fetch_array ($addonid)) {    
    $ci_counter = $db->query_read ("
      SELECT drc.mod_addons AS addon, drc.threadid, thread.threadid AS threadid, thread.title AS threadtitle
      FROM `" . TABLE_PREFIX . "modsys_settings` AS drc 
      LEFT JOIN `" . TABLE_PREFIX . "thread` AS thread ON(drc.mod_addons=" . $threadinfo['threadid'] . ") 
      WHERE thread.threadid IN (" . $addons['threadid'] . ")
    ");

    $counter = $db->fetch_array ($ci_counter);
    $post['addons'] .= 'TEST - <li><a href="showthread.php?t=' .   $addons['threadid'] . '">'. $counter['threadtitle'] .'</a></li>';
  }

  $post['addons'] .= '</ul>';
}

would do the trick but that's a no go. How do I only show the list if it has something to display?