oh , i see , thanks , but i dont see the declaration "categories AS c" in the query statement , is it a feature of mysql database ? or may it be declared somewhere at the beginning ?

PS :
I have used the mod : sub forum 1.0.4 and very satisfied but it will be much better if it shows the sub forum name in the description automatically (i know i can make it manually)
The mod has its bad config layout in the admincp : sub-forums are treated as same as forums . I want the layout to be :
forum 1
    subforum 1
    subforum 2
forum2

Can anyone guide me ? or show me which related files what i can modify myself
Thanks

forum

Hello all
I m new to PHP programming but I m really interested and would like to learn more about punBB (may be I can help write some plugins later wink )

When I read the index.php , there are codes that I dont understand , can you explain ?

$result = $db->query('SELECT c.id AS cid, c.cat_name, f.id AS fid, f.forum_name, f.forum_desc, f.redirect_url, f.moderators, f.num_topics, f.num_posts, f.last_post, f.last_post_id, f.last_poster, f.parent_forum_id FROM '.$db->prefix.'categories AS c INNER JOIN '.$db->prefix.'forums AS f ON c.id=f.cat_id LEFT JOIN '.$db->prefix.'forum_perms AS fp ON (fp.forum_id=f.id AND fp.group_id='.$pun_user['g_id'].') WHERE (fp.read_forum IS NULL OR fp.read_forum=1) AND (f.parent_forum_id IS NULL OR f.parent_forum_id=0) ORDER BY c.disp_position, c.id, f.disp_position', true) or error('Unable to fetch category/forum list', __FILE__, __LINE__, $db->error());

Why there is the prefix such as c.id , c.cat_name , f.id ? The only thing I see in phpmyadmin is id , cat_name in the table categories ?