Question

我正在尝试为私人消息创建一个用户收件箱，其中它显示两个人之间的一个最近的消息，并且最近的订单也是最近的订单。它应该像Facebook消息收件箱一样执行，您可以在其中单击最新消息的预览以查看完整对话，并且最近也会按顺序排列对话。这是我到目前为止的陈述，但它没有显示任何内容，我无法弄清楚如何解决它。有人有什么建议吗？

$sqlInbox = "
    SELECT sender, receiver, message, parent, rView
    FROM (SELECT sender, receiver, message, parent, rView
        FROM messages 
        WHERE receiver='$log_username' OR sender='$log_username'
        ORDER BY timestamp DESC)
    GROUP BY parent
    ORDER BY timestamp DESC";

父列表示完整的对话，因此无论发送或接收的是谁，两个设置的人之间的任何消息都将在表中具有相同的父ID。提前谢谢。

Answer 1

我注意到的一件事是你需要按照你选择的所有列进行分组。

SELECT sender, receiver, message, parent, rView
FROM (SELECT sender, receiver, message, parent, rView
    FROM messages 
    WHERE receiver='$log_username' OR sender='$log_username'
    ORDER BY timestamp DESC)
GROUP BY sender, receiver, message, parent, rView
ORDER BY timestamp DESC

Answer 2

检查这是否有效..

SELECT sender, receiver, message, parent, rView
FROM messages 
WHERE receiver='$log_username' OR sender='$log_username'
ORDER BY parent ASC, timestamp DESC

Answer 3

睡觉之后，逻辑来到我身边。以下似乎解决了我所有的问题。

$sqlInbox = "
    SELECT a.*
    FROM (SELECT * FROM messages
        ORDER BY timestamp DESC) AS a
    WHERE receiver='$log_username' OR sender='$log_username' 
    GROUP BY parent
    ORDER BY timestamp DESC";

如何订购行，然后对它们进行分组，然后对订单组进行分组

3 个答案: