how to insert accept/reject into db in PHP

Question

i created an appointments table where user1 would add appointments and user2 would accept/reject the appointment. now my problem is when the accept and reject are clicked it is displayed in the table respectively but i just cant understand how to add the insert query into it so that it could be inserted into the db. i tried several methods in trying to insert the state[accept/reject] into the db but i found no success. i would request someone to pls provide me some help inn fixing the issue. Thanks.

 <form method="post" action="delete.php" > 

       <table cellpadding="0" cellspacing="0" border="0" class="table table-condensed" id="example">
               <thead>
                          <tr>
                                <th>appoinment ID</th>
                              <th>Date</th>
                                <th>time</th>
                              <th>teacher</th>
                             <th>parent</th>
                              <th> accept/reject </th>
                              <th>label</th>
                            </tr>
                   </thead>
                   <tbody>
                        <?php 
                            $query=mysqli_query($conn, "select * from `app` left join `par` on par.par_id=app.par_id
                            left join `tea` on tea.tea_id=app.tea_id
                            ORDER BY app_id DESC");

                                if($query === false)
                                {
                                    throw new Exception(mysql_error($conn));
                                }
                                while($row=mysqli_fetch_array($query))
                                {
                                    $ann_id=$row['app_id'];
                                    $date=$row['date'];
                                    $msg=$row['time'];

                                    $username = $row['username'];
                                     $username = $row['p_username'];
                        ?>
                <tr>
                    <td><?php echo $row['app_id'] ?></td>
                     <td> <?php echo date('j/m/y',strtotime($row['date'])); ?></td>
                    <td><?php echo $row['time'] ?></td>
                   <td><?php echo $row['p_username'] ?></td>
                <td><?php echo $row['username'] ?></td>

                    <td>
        <a href="#" class="reject">reject</a> 
        <a href="#" class="accept">accept</a>
    </td>
    <td>
        <div class="chgtext">PENDING</div>
    </td>

                </tr>

                        <?php   
                                }

                       ?>

                  </tbody>
              </table>
         </div>
      </form>

Answer 1

One way is to pass the ID via query string (GET). So you would update the appointment if the appropriate query string key-pairs are given.

Personally, I believe you should not mix querying while outputting. Do the database stuff at the top first and leave the outputting at the bottom.

Note: I am not too familiar with mysqli_ but it would be something like this:

<?php 
// accept or reject appointment with ID
if (isset($_GET['state'], $_GET['app_id'])) {
    $stmt = mysqli_prepare($conn, "UPDATE app SET state = ? WHERE app_id = ?");
    mysqli_stmt_bind_param($stmt, "sd", $_GET['state'], $_GET['app_id']);
    mysqli_stmt_execute($stmt);
    mysqli_stmt_close($stmt);
}

// query appointments
$query = mysqli_query($conn, "
    SELECT * FROM app 
    LEFT JOIN par ON par.par_id = app.par_id
    LEFT JOIN tea on tea.tea_id = app.tea_id
    ORDER BY app_id DESC
");
?>

<form method="post" action="delete.php" > 
    <table cellpadding="0" cellspacing="0" border="0" class="table table-condensed" id="example">
        <thead>
            <tr>
                <th>appoinment ID</th>
                <th>Date</th>
                <th>time</th>
                <th>teacher</th>
                <th>parent</th>
                <th>accept/reject</th>
                <th>label</th>
            </tr>
        </thead>
        <tbody>
        <?php while($row = mysqli_fetch_array($query)) : ?>
            <tr>
                <td><?= $row['app_id'] ?></td>
                <td><?= date('j/m/y', strtotime($row['date'])) ?></td>
                <td><?= $row['time'] ?></td>
                <td><?= $row['p_username'] ?></td>
                <td><?= $row['username'] ?></td>
                <td>
                    <!-- upon clicking a link, it will redirect to the same page with a query string -->
                    <a href="?state=reject&app_id=<?= $row['app_id'] ?>" class="reject">reject</a> 
                    <a href="?state=accept&app_id=<?= $row['app_id'] ?>" class="accept">accept</a>
                </td>
                <td>
                    <div class="chgtext">PENDING</div>
                </td>
            </tr>
        <?php endwhile ?>
        </tbody>
    </table>
</form>