我的循环中的数据不匹配，不确定原因

Question

I have a code that is suppose to display messages back and forth between the users. For some reason the data is mismatching and I'm not sure where in my code I have the error. I've tried to change my if statements of $x < $sender but that didn't work.

but the data being displayed doesn't line up with the database information.

"Test 2" message was sent from woof3, so it should be green and not blue when logged in as woof. And "test again" was sent from woof, so it should be blue when logged in as woof

Edit working code down below, no pdo because I'm not done with this project and I save those for the end to make testing easier.

<?php

include "../Site/db.php";

$url = $_SERVER['REQUEST_URI'];
$urlArray = explode('=', $url);
$Username = $urlArray[sizeof($urlArray) - 1];

$Myself = $_SESSION['username'];

$sql = "SELECT * FROM messages ORDER BY `Id` ASC";
$result = $conn->query($sql);

// Header of message box
echo '<div id="messages" class="messagePersonBox shadow">
        <span class="usersname" name="receiver"><a href="Account?='.$Username.'">'.$Username.'</a></span>
<hr style="margin-top:24px">
<div id="allMessages"class="allMessages">
';

// $sql2 = "SELECT * FROM messages WHERE Sender = '$Myself' ORDER BY `Id` ASC";
// $result2 = $conn->query($sql2);

$sql3 = "SELECT *  FROM messages 
        WHERE (Sender = '$Myself' AND Receiver = '$Username')
           OR (Receiver = '$Myself' AND Sender = '$Username') ORDER BY `MessageTime` ASC";


$result3 = $conn->query($sql3);
print_r($result3);
$x = 0;

$sql4 = "SELECT * FROM messages WHERE Sender = '$Myself'";
$result4 = $conn->query($sql4);

$sql5 = "SELECT * FROM messages WHERE Receiver = '$Myself'";
$result5 = $conn->query($sql5);

$totalSender = mysqli_num_rows($result4);
$totalReceiver = mysqli_num_rows($result5);

// might have to add both totals for while loop
// to get total messages
$totalmessages = mysqli_num_rows($result);

// For receiving
while ($x < $totalmessages) {

    // output data of each row

     if ($result3->num_rows > 0) {
         if ($row = $result3->fetch_assoc()) {
             $Sender = $row['Sender'];
             $Message = $row['Message'];
             $Receiver = $row['Receiver'];
             $TimeSent = $row['MessageTime'];
         }
     }
       $class = $Sender == $Myself ? 'messageDisplay' : 'messageDisplay2';


     // sending a message

         echo '<div id="messages2" class="'.$class.'">'.$Message.'<span style="float: right;margin-top:2px"><font size=1>'.time_elapsed_string($TimeSent).'</span></font></div>';



$x++;
}

// Typing part of message
echo '</div>
      <input type="text" id="messagetosend" name="message" class="messagetype" placeholder="Type a message..."><span id="send" class="messageSend">↩</span>

</div>';
?>

I can add more info if needed.

Answer 1

I suggest you take a step back and restructure this approach a bit.

For instance, you don't need conversationID (at least not in its current format), as you can deduct it from Sender and Receiver, which is more accurate. You also don't need MessageDate, since MessageTime is a datetime value that holds both the date and the time. So, conversationID and MessageDate can be removed.

Then, we can clean up the number of queries. You want to get all messages where you are the sender and the other user is the recipient, or where you are the recipient and the other user is the sender of that message. We then sort by date (not the ID!), and check if the message should be green or blue based on the Sender value of that row - set a $class variable with one value for blue if the sender is the current user, green otherwise.

As a note, when outputting blocks of HTML, you can exit PHP, which makes it easier to read (and deal with quotes). You also had HTML elements with the same ID, which is not allowed.

You should also be using prepared statements when dealing with variables in a query.

<?php

include "../Site/db.php";

$url = $_SERVER['REQUEST_URI'];
$urlArray = explode('=', $url);
$Username = $urlArray[sizeof($urlArray) - 1];

$Myself = $_SESSION['username'];

$sql = "SELECT Message, MessageTime, Sender, Receiver
        FROM messages 
        WHERE (Sender = ? AND Receiver = ?)
           OR (Receiver = ? AND Sender = ?)
        ORDER BY `MessageTime` ASC");
if (!$stmt = $conn->prepare($sql)) {
    error_log($conn->error);
    die("An error occurred fetching messages");
}
$stmt->bind_param("ssss", $Myself, $Username, $Myself, $Username);
$stmt->bind_result($message, $timeSent, $sender, $received);
if (!$stmt->execute()) {
    error_log($stmt->error);
    die("An error occurred fetching messages");
}
?>
<!-- Header of message box -->
<div id="messages" class="messagePersonBox shadow">
    <span class="usersname" name="receiver"><a href="Account?=<?php echo $Username; ?>"><?php echo $Username; ?></a></span>
    <hr style="margin-top:24px">
    <div id="allMessages" class="allMessages">
        <?php 
        while ($stmt->fetch()) {
            $class = $sender == $Myself ? 'messageDisplay' : 'messageDisplay1'; // Check which class should be used; if I'm the sender, show messageDisplay, if not show MessageDisplay1 
            ?>
            <div class="<?php echo $class; ?>
                <?php echo $message; ?>
                <span style="float: right; margin-top: 2px">
                    <?php echo time_elapsed_string($timeSent); ?>
                </span>
            </div>
            <?php 
        }
        ?>
    <!-- Typing part of message -->
    </div>
    <input type="text" id="messagetosend" name="message" class="messagetype" placeholder="Type a message..."><span id="send" class="messageSend">↩</span>
</div>
<?php 
$stmt->close();