PHP を使用して受信トレイ管理機能を実装するにはどうすればよいですか?

CREATE TABLE emails (
  id INT(11) AUTO_INCREMENT PRIMARY KEY,
  sender VARCHAR(255),
  receiver VARCHAR(255),
  subject VARCHAR(255),
  content TEXT,
  sent_at DATETIME
);

<?php
// 连接到数据库
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database";

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

// 获取收件箱中的邮件
$sql = "SELECT * FROM emails WHERE receiver = 'user@example.com'";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
  // 输出每封邮件的信息
  while($row = $result->fetch_assoc()) {
    echo "发件人：" . $row["sender"]. " - 主题：" . $row["subject"]. "<br>";
  }
} else {
  echo "收件箱为空";
}

$conn->close();
?>

<?php
// 连接到数据库
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database";

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

// 删除指定邮件
$emailId = $_GET["id"];
$sql = "DELETE FROM emails WHERE id = $emailId";
if ($conn->query($sql) === TRUE) {
  echo "邮件删除成功";
} else {
  echo "邮件删除失败：" . $conn->error;
}

$conn->close();
?>