LEFT JOIN help

[assassingod]

I need to grab info from 1 column from a different table from the one im selecting. I'm assuming its a left join but i may be wrong

PHP Code:

        $news = $DB_site->query("
        SELECT thread.threadid,thread.title,thread.replycount,thread.postusername,thread.postuserid,thread.dateline,thread.views,thread.iconid
        FROM thread
        WHERE forumid = '5'
        ORDER BY thread.dateline DESC
        LIMIT 3
    "); 


I tried using 'LEFT JOIN post ON post.pagetext=thread.pagetext' then selecting thread.pagetext in the SELECT bit, but didn't work.

Anyone help me?

(BTW, I do have my while loop code, I just didn't include it there)

I still haven't understood LEFT JOIN's properly