Left Join SQL Help

Im trying to write a "Left Join" sql statement.
There are 4 tables in a similar structure to ->
[user table]
user_id - username

[user2 table]
uid - user_regdate

[post table]
post_id - poster_id

[posts_text table]
post_id - post_text

[whosonline table]
uid - session_id

This is the sql that Im using ->
SELECT u.user_id, u2.user_regdate, p.post_id, w.uid FROM posts p LEFT
JOIN posts_text pt ON p.post_id = pt.post_id LEFT JOIN users u ON
p.poster_id = u.user_id LEFT JOIN users2 u2 ON p.poster_id = u2.uid LEFT
JOIN whosonline w ON p.poster_id = w.uid WHERE topic_id =
'AFAdDFoAPjvgJNzj' ORDER BY post_time LIMIT 10 OFFSET 0;

If the whosonline table has more than one entry for "anonymous user" id
-1, the sql reports 5 rows.
The 2 last rows should just be one row.

user_id | user_regdate | post_id | uid
------------------+--------------+------------------+-----
1 | 1009861200 | a |
1 | 1009861200 | b |
1 | 1009861200 | c |
-1 | 0 | d | -1
-1 | 0 | d | -1
(5 rows)

Any help in this matter would be appreciated. Thanks.

--
Gerard Samuel
http://www.trini0.org:81/
http://dev.trini0.org:81/