mysqli查询函数

$mysqli = new mysqli("localhost", "username", "password", "database");

if ($mysqli->connect_error) {
    die("连接失败: " . $mysqli->connect_error);
}

$sql = "SELECT * FROM users WHERE id = ?";
$stmt = $mysqli->prepare($sql);
$stmt->bind_param("i", $userId);

if ($stmt->execute()) {
    $result = $stmt->get_result();
    while ($row = $result->fetch_assoc()) {
        // 处理结果集
    }
} else {
    echo "查询失败: " . $mysqli->error;
}

$sql = "INSERT INTO users (name, email) VALUES (?, ?)";
$stmt = $mysqli->prepare($sql);
$stmt->bind_param("ss", $name, $email);

$name = "John Doe";
$email = "john.doe@example.com";

if ($stmt->execute()) {
    echo "插入成功";
} else {
    echo "插入失败: " . $stmt->error;
}