Quick snippet code - getting dupbicates! Need PHP / MySQL help

Hi,

I'm using the following code - a modified version of something from the quick snippet pages. I'm not skilled (obviously) in PHP or SQL, so it is very likely that it was something in my modifications that has created the problem!

<?php
  $listlength="4";
  $content_type = 'page';
  $taxo_id = 8;
  $content_type2 = 'bookreview';
  $result1 = pager_query(db_rewrite_sql("SELECT n.nid, n.created FROM {node} n INNER JOIN term_node ON n.nid = term_node.nid WHERE n.type IN('$content_type', '$content_type2') AND n.status = 1 AND term_node.tid NOT LIKE $taxo_id ORDER BY n.created DESC"), $listlength);
  while ($node = db_fetch_object($result1)) {
    $output .= node_view(node_load(array('nid' => $node->nid)), 1);
  }
print $output;
?>

What I was aiming to do was post the 4 most recent additions to the site which had a content type of either Page or Book Review. But, I also wanted to exclude pages that had the taxonomy term of "siteadmin", i.e. taxo_id 8.

The query seems to be working, but I am getting duplicate outputs for all bookreviews. Are bookreviews somehow also pages?
Is there a way to check the results and filter out duplicates from the output?