AJAX聊天 - 按日期，时间排序（消息从底部显示，最顶部将被删除）？

Question

I have a chat application I have been developing:

http://driptone.com/jony/applications/chat/index.php

Problem is, I am limiting results of messages at 30 messages maximum. I want new messages to overwrite, so the oldest messages will get deleted, from the top.

But for some reason, the messages on the bottom, which are the new ones, get deleted instead? By deleted I mean, won't show.

How can I change it?

I am ordering by date, time:

SELECT * FROM messages ORDER BY date, time ASC LIMIT 30

Inside while loop:

echo 
'
    <li>
        <div class="messages">
            <p>
                '.$row['message'].'
            </p>
            <span class="user-meta">
                '.$row['username'].'
            </span>
            <span class="time-meta">
                '.$row['time'].', '.$row['date'].'
            </div>
        </div>
    </li>
';

Any ideas?

Answer 1

select * from(SELECT * FROM messages ORDER BY date, time desc LIMIT 30) as main order by date,time asc