too long

Im trying to create a dynamic web page in php and mysql. I have the below code on the profile.php page. The issue im having is on the "while" line im not sure how i would go about getting the information from the DB. I want to display details like email, country First name, etc. Any help appreciated. Thanks in advance! CODE:

$userid = (isset($_GET['id']) ? $_GET['id'] : NULL);

if ($userid) {
    $userinfo = $DB->query_first("SELECT * FROM `users` WHERE `id` = '$userid'");
    print_r($userinfo);
    }
        //{
            while($row = sql_fetch_assoc($DB)){

                echo'<div class="container">
            <div class="jumbotron" align="block">';
                echo $row['first_name'];
            echo $row['last_name'];
            echo $row['country'];
                echo $row['username'];
            echo'</div>';
            echo'</div>';
            }

Try by using this

<?php
$userid = (isset($_GET['id']) ? $_GET['id'] : NULL);

if ($userid) {
   $userinfo = $DB->query_first("SELECT * FROM `users` WHERE `id` = '$userid'");
   print_r($userinfo);
?>
<table>
<tr>
    <td>First Name</td>
    <td><?=$userinfo['first_name']?></td>
</tr>
<tr>
    <td>Last Name</td>
    <td><?=$userinfo['last_name']?></td>
</tr>
............
............
</table>
<?php } ?>

do not use null use a empty string "" that is what you want sql well do nothing with an empty string it is just white space, enough about sql injection attacks wtf ever topic i enter. actually make it equal to wither where userid='$userid' or "". there is only one row so the while statement is redundant just row = mysql_fetch_array.

You can try something like this:

<?php
    $userid = (isset($_GET['id']) ? $_GET['id'] : NULL);

    if ($userid) {
       $userinfo = $DB->query_first("SELECT * FROM `users` WHERE `id` = '$userid'");
       print_r($userinfo);
       echo'
           <div class="container">
               <div class="jumbotron" align="block">
                   '.$userinfo['first_name'].' <br>
                   '.$userinfo['last_name'].' <br>
                   '.$userinfo['country'].' <br>
                   '.$userinfo['username'].' <br>
               </div>
           </div>';
?>