如何从消息表中查找最后一条消息并查找用户

Question

这是我的用户表 这是我的消息表

这是我的清单表

现在我成功获得了此查询的最后一条消息

enter code here
$coreQueryUser = $this->Message->query('
            select m.*
            from
                messages m
                inner join (
                select max(id) as maxid
                from messages
                where messages.list_id = 3 
                group By (if(sender_id > reciever_id,  sender_id, reciever_id)), 
                (if(sender_id > reciever_id,  reciever_id, sender_id))
               ) t1 on m.id=t1.maxid 
        ');

当我运行此查询时，它给出了以下输出： -

enter code here
<pre>Array
(
[0] => Array
    (
        [m] => Array
            (
                [id] => 2
                [sender_id] => 10
                [reciever_id] => 21
                [list_id] => 3
                [message] => hello sir
                [add_date] => 2016-09-25 08:24:38
                [is_check] => 0
            )

    )

[1] => Array
    (
        [m] => Array
            (
                [id] => 7
                [sender_id] => 10
                [reciever_id] => 22
                [list_id] => 3
                [message] => hmm
                [add_date] => 2016-09-27 00:00:00
                [is_check] => 0
            )

    )
)

现在您在输出中看到第一个数组sender_id = 10和reciver_id = 21     和list_id = 3 列表由id为10的用户创建。在输出中我想获取用户ID为21的用户数据。请记住，当接收者将消息发送给发件人时，ID正在互换。在这种情况下，我还想要用户ID为21的数据

请帮帮我:(

Answer 1

我找到了自己的解决方案

enter code here
$coreQueryUser = $this->Message->query('
            select m.* ,u.*
            from
                messages m
                inner join (
                select max(id) as maxid
                from messages
                where messages.list_id = " '. $data['list_id'] .'" 
                group By (if(sender_id > reciever_id,  sender_id, reciever_id)), 
                (if(sender_id > reciever_id,  reciever_id, sender_id))
               ) t1 on m.id=t1.maxid 
                join 
                users u  ON u.id = (CASE WHEN m.sender_id = 10
                                   THEN m.reciever_id
                                   ELSE m.sender_id        
                               END)
        ');