$sql = 'SELECT
        forum_topics.topic_id,
        forum_topics.plid,
        forum_topics.subject,
        UNIX_TIMESTAMP(forum_posts.date) AS dateposted,
        forum_posts.plid,
        FROM 
        forum_topics
        INNER JOIN 
        forum_posts
        ON
        forum_topics.topic_id = forum_posts.topic_id 
        WHERE
        forum_topics.forum_id='.$forum_id.'
        AND forum_topics.sub_id='.$forum_sub_id.'
        ORDER BY dateposted DESC';