MYSQLI_ASSOC and MYSQLI_NUM
 // mysqli_fetch_array($query)                          [General and simple Process]  while ($row = mysqli_fetch_array($query)) {          ?>          <tr>              <td><?php echo $row['id']; ?></td>              <td><?php echo $row['name']; ?></td>              <td><?php echo $row['roll']; ?></td>              <td><?php echo $row['created_date']; ?></td>          </tr>          <?php      }   // MYSQLI_ASSOC         ...