or something like this:
PHP Code:
<?
$result = mysql_query("select c.category_name, count(a.article_id) as count from np_categories as c
left join np_articles as a on c.category_id=a.article_category_id
group by c.category_id
order by c.category_name");
while ($row = mysql_fetch_assoc($result)) {
echo $row['category_name'] . " (" . $row['count'] . ")<br />\n";
}