looping database results using MySQLi

Question

I am trying to pull a list of registration information from MySQL. I'm changing the query over to object oriented and when I did this, the results are not being displayed inside the table. No error messages are being displayed.

<?php   

                    $sql     = "SELECT * FROM `prereg`";
                    if (!$stmt = $mysqli->query("SELECT * FROM prereg")) {
                        echo "Query Failed!: (" . $mysqli->errno . ") ". $mysqli->error;
                    }else{

                    while ($row = mysqli_fetch_assoc()) {                                   
            ?>
                <tr>
               <!-- <td>
                        <?php echo $row['UID']; ?>
                    </td> -->
                    <td>
                        <?php echo $row['Guradian']; ?>
                    </td>
                    <td>
                        <?php echo $row['Number']; ?>
                    </td>
                    <td>
                        <?php echo $row['Phone']; ?>
                    </td>
                    <td>
                        <?php echo $row['Name']; ?>
                    </td>
               <!-- <td>
                        <?php echo $row['Address']; ?>
                    </td> -->
                    <td>
                        <?php echo $row['City']; ?>
                    </td>
                    <td>
                        <?php echo $row['State']; ?>
                    </td>
               <!-- <td>
                        <?php echo $row['Zip']; ?>
                    </td>
                    <td>
                        <?php print $row['Make']; ?>
                    </td> 
                    <td>
                        <?php print $row['Ms']; ?>
                    </td> -->
                    <td>
                        <?php print $row['Fuel']; ?>
                    </td>
                    <td>
                        <?php echo $row['Class1']; ?>
                    </td>
                    <td>
                        <?php print $row['Class2']; ?>
                    </td>
                    <td>
                        <?php print $row['Class3']; ?>
                    </td>
                </tr>
                        <?php } }
                    $stmt->free(); ?>

What am I doing wrong? I've searched and searched and I cannot find anything that fixes the problem.

REVISED:

<?php   
                    $stmt = $mysqli->query("SELECT * FROM prereg");
                    if($stmt->num_rows > 0):
                        while ($row = $stmt->fetch_assoc()):                                    
            ?>
                <tr>
               <!-- <td>
                        <?php echo $row['UID']; ?>
                    </td> -->
                    <td>
                        <?php echo $row['Guradian']; ?>
                    </td>
                    <td>
                        <?php echo $row['Number']; ?>
                    </td>
                    <td>
                        <?php echo $row['Phone']; ?>
                    </td>
                    <td>
                        <?php echo $row['Name']; ?>
                    </td>
               <!-- <td>
                        <?php echo $row['Address']; ?>
                    </td> -->
                    <td>
                        <?php echo $row['City']; ?>
                    </td>
                    <td>
                        <?php echo $row['State']; ?>
                    </td>
               <!-- <td>
                        <?php echo $row['Zip']; ?>
                    </td>
                    <td>
                        <?php print $row['Make']; ?>
                    </td> 
                    <td>
                        <?php print $row['Ms']; ?>
                    </td> -->
                    <td>
                        <?php print $row['Fuel']; ?>
                    </td>
                    <td>
                        <?php echo $row['Class1']; ?>
                    </td>
                    <td>
                        <?php print $row['Class2']; ?>
                    </td>
                    <td>
                        <?php print $row['Class3']; ?>
                    </td>
                </tr>
                        <?php endwhile; endif; ?>
            </table>

            <?php
            $stmt = $mysqli->query("SELECT * FROM prereg"); 

             if($stmt->num_rows > 0): ?>
                <table>
            <?php while($row = $stmt->fetch_assoc()): ?>
                    <tr>
                    <?php foreach($row as $val): ?>
                        <td><?php echo $val; ?></td>
                    <?php endforeach; ?>
                    </tr>
            <?php endwhile; ?>
            </table>
        <?php endif; ?>
        </center>

when trying to retrofit the code you have provided with the table I already had, the code you gave works, the table I have still wont populate.

Answer 1

If you are using the procedural interface mysqli_fetch_assoc(), you need to provide the mysqli_result.

while ($row = mysqli_fetch_assoc($stmt)) { 

If you'd use the object oriented interface, then just use it as its method:

while($row = $stmt->fetch_assoc()) {

Revised:

<?php 
$mysqli = new mysqli('localhost', 'username', 'password', 'database_name');
$stmt = $mysqli->query('SELECT * FROM prereg');
?>

<?php if($stmt->num_rows > 0): ?>
<table>
    <?php while($row = $stmt->fetch_assoc()): ?>
        <tr>
        <?php foreach($row as $val): ?>
            <td><?php echo $val; ?></td>
        <?php endforeach; ?>
        </tr>
    <?php endwhile; ?>
</table>
<?php else :?>
<p>Table empty</p>
<?php endif; ?>