Question

假设我有一个包含这样的数据的数据库

id  userfrom userto body
1   a         b      hello
2   b         a      i am b
3   a         b      everyone
4   b         a      this is great

现在我想选择每个a和b中的1个或者你可以说我只想显示a和b的1个帖子所以应该是这个在php中的mysql查询和我的查询就像这样告诉我什么我必须接受更改以获取数据抱歉写这么长的代码

<?php
                                $connection10=mysqli_connect('localhost','root','123456789','register');
        $selectquery="select * from messages where userfrom='$msg' or userto='$msg'";
        $resultquery=mysqli_query($connection10,$selectquery);
while($rowstand=mysqli_fetch_array($resultquery))
        {
            $userfrom1=$rowstand['userfrom'];
            $userto1=$rowstand['userto'];
            $body=$rowstand['msgbody'];
                $date=$rowstand['date'];
        $searchquery="select * from register where id='$userto1'";
            $searchresult=mysqli_query($connection10,$searchquery);
            while($bigrow=mysqli_fetch_array($searchresult))
            {
                $profileimage=$bigrow['profilepic'];
            $myfirstname=$bigrow['firstname'];
            $mylastname=$bigrow['lastname'];
            }
        echo '<a href="viewmessages.php?id='.$userto1.'"><img src="'.$profileimage.'" height="50" width="50"></a>'.$myfirstname.' '.$mylastname.'<br>'.$body.'<hr>';}
?>

Answer 1

select DISTINCT name,id,post from users

或

select DISTINCT name,id,post from users GROUP BY name

Answer 2

您可以使用GROUP BY执行此操作，这将在您的示例中返回2个结果。使用GROUP_CONCAT连接属于同一名称的帖子可能会很好：

SELECT name, GROUP_CONCAT(post SEPARATOR ' ') 
FROM users
GROUP BY name;

输出：

a |大家好，

b |我是b这很棒

Fiddle

Answer 3

您可以使用GROUP BY命令，如下所示： http://sqlfiddle.com/#!9/a0057/5/0

如何从php

3 个答案: