PHP を使用して WeChat アプレットのタスク統計機能を開発するにはどうすればよいですか?

<button open-type="getUserInfo" bindgetuserinfo="onGetUserInfo">登录</button>

onGetUserInfo: function (res) {
  if (res.detail.userInfo) {
    wx.login({
      success: function (loginRes) {
        if (loginRes.code) {
          wx.request({
            url: 'https://api.weixin.qq.com/sns/jscode2session',
            data: {
              appid: '小程序的AppID',
              secret: '小程序的AppSecret',
              js_code: loginRes.code,
              grant_type: 'authorization_code'
            },
            success: function (res) {
              var openid = res.data.openid;
              // 将openid保存到本地或发送到后台服务器
            }
          });
        }
      }
    });
  }
}

<?php
$openid = $_POST['openid']; // 接收前端传递的openid参数

// 将openid保存到数据库
$servername = "localhost";
$username = "用户名";
$password = "密码";
$dbname = "数据库名";

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

$sql = "INSERT INTO users (openid) VALUES ('$openid')";
if ($conn->query($sql) === TRUE) {
  echo "保存成功";
} else {
  echo "Error: " . $sql . "<br>" . $conn->error;
}

$conn->close();
?>

<?php
$openid = $_POST['openid']; // 接收前端传递的openid参数

// 查询用户的任务
$servername = "localhost";
$username = "用户名";
$password = "密码";
$dbname = "数据库名";

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

$sql = "SELECT COUNT(*) as count FROM tasks WHERE openid = '$openid'";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
  while($row = $result->fetch_assoc()) {
    $count = $row["count"];
    echo "用户的任务数量：" . $count;
  }
} else {
  echo "用户没有任务";
}

$conn->close();
?>