PHP浏览器中的SQL查询问题不显示搜索结果[重复]

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in my web app I have friends search and i don't know why, but it doesn't show errors and browser doesn't show anything when I'm writing username to search. Can anyone help me find that error? :D My code look like this:

<div class="input">
    <input type="text" class="finder" value="Find friends by username" name="friends">
    </div>
    <div class="friends"> 
    <?php 
     require_once "connect.php";
     mysqli_report(MYSQLI_REPORT_STRICT);
     $connection= mysqli_connect($host, $db_user, $db_password, $db_name);
     if(mysqli_connect_errno()) {
       echo "Server error. Try again later.";
     } else {
       $friends = $_POST['friends'];
     $result=$connection->query("SELECT username FROM users WHERE username = '$friends'");
     $row = mysqli_fetch_assoc($result);
     $username = $row['username'];
     $how_much_friends = $result->num_rows;
     if($how_much_friends=0) {
         $_SESSION['e_friends']= '<span style="color:white"> We did not found your friends on CD Messenger. </span>';
     } else {
       while($row) {
           if (isset($_SESSION['e_friends']))
           {
           echo $_SESSION['e_friends'];
           unset($_SESSION['e_friends']);
           } else {
            echo "<div>" .  $username . "</div>";
           }
       }

     }

     }
       $connection->close();
    ?>
    </div>
</div>