html下拉列表获取MySQL中的数据

Question

*我想从下拉列表中获取数据，就像我选择了代理ID和代理名称来获取数据库中的数据我将代理ID存储在数据库表中 代理ID中的错误未存储在数据库中

<?php
$sql = mysqli_query($con, "SELECT agent_name From agent order by agent_id");
$row = mysqli_num_rows($sql);
while ($row = mysqli_fetch_array($sql)){
  echo "<option value='" . $row['agent_id'] . "'>" . $row['agent_name'] . "</option>";

    }
    ?>
    </select>



    <label>Agent</label>
     <select class="form-control" name="agent_name" id="agent_name">

Answer 1

  <?php
  $sql = mysqli_query($con, "SELECT agent_name,agent_id From agent order by           agent_id");
  $num = mysqli_num_rows($sql);
  ?>
  <label>Agent</label>
  <select class="form-control" name="agent_name" id="agent_name">
  <?php
   while ($row = mysqli_fetch_array($sql)){
   echo "<option  value='".$row['agent_id']."'>".$row['agent_name'] . "</option>";
   }
   ?>
   </select>