消息对话 php

Question

我在messages.php上创建了消息系统，我想明智地显示消息对话，应该显示最后一条消息，但不知道查询，因为我是php新手，这里是数据库信息

  table:conversation_chat            table2:chat
 conversation_id: primary unique    id: primary unique 
 from:                              conversation_id: 
 to:                                from_user:
 time:                              to_user:
                                    message:
                                     subject:

如果有人可以帮助我，请

 <?php

  $req3 = mysql_query("SELECT * FROM `conversation_chat` WHERE 
  `user_to`='$userid1'");
 $hy= mysql_fetch_array($req3);

  $convo = $hy['conversation_id'];

  if(mysql_num_rows($req3)!=0){

  $req4 = mysql_query("SELECT * FROM `chat` WHERE `to`='$userid1' AND  

  `conversation_id`='$convo'");
      while($dn1 = mysql_fetch_array($req4))
   { 
  ?>

 <td><img alt="example image" src="avatar.png"> &nbsp; &nbsp; <a 
 href="read?id=<?php echo $dn1['id']; ?>"><?php echo
 htmlentities($dn1['from'], ENT_QUOTES, 'UTF-8'); ?></a></td>



                  <td><span class="label vd_bg-green append-icon">

 <?php  
 echo $dn1['subject']; ?></span></td>
                  <td style="width:80px" class="text-right"> 

 <strong><?php echo timeAgo($dn1['time']); ?></strong></td><td 

 style="width:80px" class="text-right">
 <?php echo '<a 
 href="mdelete.php?id='. $dn1['id'] .'">Delete</a>'; ?></td>
                </tr>
                <?php
 }}else{ echo "No new messages";}
 ?>

Answer 1

好的，您刚刚编辑了数据库信息。 所以现在我明白了你的数据库是怎样的。

你必须在chat2中添加一个DATETIME类型的“时间”列

SELECT * 

FROM `chat` 

WHERE `to`='$userid1' 

AND  

  `conversation_id`='$convo'    

ORDER BY time DESC //Change the order from last to older

如果你只想要最后一条消息，如果它是 MySQL 数据库，你可以添加

LIMIT 1

Answer 2

如果我正确理解了您的问题，您希望仅显示一条消息。即最新的？

如果是这样，请更改您的查询

SELECT * FROM `chat` ...

到

SELECT *, max(date) FROM `chat` ...

选择

Answer 3

<?php

  $req3 = "SELECT DISTINCT conversation_id,column_name FROM `conversation_chat` WHERE 
  `user_to`='$userid1' ORDER BY conversation_id desc";
$query=mysql_query($req3);
$num=mysql_num_rows($req3);
 $hy= mysql_fetch_array($req3);

  $convo = $hy['conversation_id'];

  if($num!=0){

  $req4 = mysql_query("SELECT DISTINCT id,column_name FROM `chat` WHERE `to`='$userid1' AND  

  `conversation_id`='$convo' ORDER BY id desc ");
      while($dn1 = mysql_fetch_array($req4))
   { 
  ?>

 <td><img alt="example image" src="avatar.png"> &nbsp; &nbsp; <a 
 href="read?id=<?php echo $dn1['id']; ?>"><?php echo
 htmlentities($dn1['from'], ENT_QUOTES, 'UTF-8'); ?></a></td>



                  <td><span class="label vd_bg-green append-icon">

 <?php  
 echo $dn1['subject']; ?></span></td>
                  <td style="width:80px" class="text-right"> 

 <strong><?php echo timeAgo($dn1['time']); ?></strong></td><td 

 style="width:80px" class="text-right">
 <?php echo '<a 
 href="mdelete.php?id='. $dn1['id'] .'">Delete</a>'; ?></td>
                </tr>
                <?php
 }}else{ echo "No new messages";}
 ?>