从数据库中获取由发件人分组的最后一封邮件的查询是什么? - What would be the query to get last mail grouped by the sender from Database

What would be the query to get last mail grouped by the sender from Database

我只想打印出发件人的最后一封邮件。这是我的PHP代码，我需要使用这个

$resultmsg=mysql_query("SELECT * FROM mails WHERE  Recieve=$AID GROUP BY Sender DESC ORDER BY ID DESC LIMIT 5 ",$con);
                            while($rowmsg=mysql_fetch_array($resultmsg) )
    {
$authormsg=$rowmsg['Sender'];
$id=$rowmsg['ID'];
$date=$rowmsg['Date'];
$state=$rowmsg['State'];
$sqlnamea=mysql_query("SELECT * FROM users WHERE ID=$authormsg");
                            $datauthor=mysql_fetch_object($sqlnamea);
$authorname=$datauthor->Lname;
$authormsgpic=$datauthor->Profpic;
echo"
<li dir='rtl' style='border-bottom:1px solid silver;";
if($rowmsg['State']=='new')echo "border-right:2px solid #FFAEAF;";
 echo"' class='postedArticle' id='$id postedArticle' ><a href='sendmsg.php?from=".$authormsg."' style='float:right;' target=home><img style='float:right;max-width:40px;max-height:40px;margin-bottom:3px;' src='images/usrimgs/".$authormsgpic."' />&nbsp".$authorname."</a>&nbsp".$rowmsg["Content_text"]."";

将限制更改为1:

SELECT * FROM收件人=$AID GROUP BY Sender DESC ORDER BY ID DESC LIMIT 1

  SELECT x.* 
    FROM mails x
    JOIN
       ( SELECT sender,MAX(id) max_id FROM mails GROUP BY sender ) y
      ON y.sender = x.sender
     AND y.max_id = x.id;