$sql_exclude_cats = '';
    if (!empty($excluded_categories)) {
### ronr hack BEGIN ###
        # find ids of all posts in excluded cats
        $query =
            "SELECT post_id
             FROM $wpdb->post2cat
             WHERE category_id IN ("
             . str_replace(',', ',', $excluded_categories)
             . ')';
        $excluded_post_rows = $wpdb->get_results($query);
 
        # build IN clause from those ids
        if (count($excluded_post_rows) > 0) {
            $sql_exclude_cats =
                ' AND ID NOT IN ('
                . intval($excluded_post_rows[0]->post_id);
            for ($i = 1; $i < (count($excluded_post_rows)); $i++) {
                $sql_exclude_cats .= ',' . intval($excluded_post_rows[$i]->post_
id);
            }
            $sql_exclude_cats .= " )";
        }
### ronr hack END ###
    }