Php 在更新表单中预填充选择输入字段

我正在为php/mysql应用程序中的数据创建一个更新表单。要根据现有数据预填充更新表单中输入type=“text”字段的值，我使用以下代码：

<label for="username">Username:</label>
<input name="username" type="text" value="<?php echo htmlentities($username, ENT_COMPAT, 'utf-8'); ?>">

用户名：
试试这个

 <label for="user_role">User Role:</label>
    <select name="user_role">
       <option value="">Select User Role</option>
    <?php
       // get results
       $query = 'SELECT userid, user_role FROM users_profile ORDER BY user_role';
       $results = $conn->query($query);
       while ($row = $results->fetch_assoc()) {
           $selected='';
           if($row['user_role']==$update_id['user_role']) // put your update user_role here
           $selected='selected="selected"';
           ?>
       <option value="<?php echo $row['user_role']; ?>" <?php  echo $selected; ?>><?php echo $row['user_role']; ?></option>
    <?php } ?>
    </select> 

用户角色：
选择用户角色

 <label for="user_role">User Role:</label>
    <select name="user_role">
       <option value="">Select User Role</option>
    <?php
       // get results
       $query = 'SELECT userid, user_role FROM users_profile ORDER BY user_role';
       $results = $conn->query($query);
       while ($row = $results->fetch_assoc()) {
           $selected='';
           if($row['user_role']==$update_id['user_role']) // put your update user_role here
           $selected='selected="selected"';
           ?>
       <option value="<?php echo $row['user_role']; ?>" <?php  echo $selected; ?>><?php echo $row['user_role']; ?></option>
    <?php } ?>
    </select>