在php函数中使用sql查询获取结果时出现问题[已关闭]

$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database_name";

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

// 检查连接
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

$sql = "SELECT id, name FROM users WHERE age > 25";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    // 输出数据
    while($row = $result->fetch_assoc()) {
        echo "id: " . $row["id"]. " - Name: " . $row["name"]. "<br>";
    }
} else {
    echo "0 结果";
}

GRANT SELECT, INSERT, UPDATE, DELETE ON database_name.* TO 'username'@'localhost';
FLUSH PRIVILEGES;

$conn->set_charset("utf8");

ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);

// 或者使用 try-catch 捕获异常
try {
    $result = $conn->query($sql);
} catch (Exception $e) {
    echo "查询失败: " . $e->getMessage();
}