mysqlquery返回false

<?php
// 数据库连接配置
$host = 'localhost';
$dbname = 'your_database';
$user = 'your_username';
$pass = 'your_password';

try {
    // 创建PDO实例
    $pdo = new PDO("mysql:host=$host;dbname=$dbname;charset=utf8", $user, $pass);

    // 执行查询
    $sql = "SELECT * FROM your_table WHERE id = :id";
    $stmt = $pdo->prepare($sql);
    $stmt->bindParam(':id', $id, PDO::PARAM_INT);
    $id = 1; // 假设要查询的ID为1
    $result = $stmt->execute();

    if ($result) {
        // 查询成功，处理结果集
        $rows = $stmt->fetchAll(PDO::FETCH_ASSOC);
        print_r($rows);
    } else {
        // 查询失败，输出错误信息
        echo "Query failed: " . $pdo->errorInfo()[2];
    }
} catch (PDOException $e) {
    // 捕获并处理异常
    echo "Connection failed: " . $e->getMessage();
}
?>