如何在PHP和mysql中添加多个具有不同用户id的复选框

<?php
// 连接数据库
$servername = "localhost";
$username = "root";
$password = "password";
$dbname = "mydb";

$conn = new mysqli($servername, $username, $password, $dbname);
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

// 查询用户信息
$sql = "SELECT 用户ID, 用户名 FROM 用户表";
$result = $conn->query($sql);

// 显示复选框
if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {
        echo "<input type='checkbox' name='checkbox[]' value='" . $row["用户ID"] . "'>" . $row["用户名"] . "<br>";
    }
} else {
    echo "没有用户信息";
}

// 处理表单提交
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    if(isset($_POST['checkbox'])){
        foreach($_POST['checkbox'] as $checkbox){
            // 更新数据库
            $sql = "UPDATE 用户表 SET 复选框状态 = '选中' WHERE 用户ID = '" . $checkbox . "'";
            if ($conn->query($sql) === TRUE) {
                echo "复选框状态更新成功";
            } else {
                echo "Error: " . $sql . "<br>" . $conn->error;
            }
        }
    }
}

$conn->close();
?>