php mysqli的查删改

$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()) {
    // 查询成功
} else {
    echo "查询失败: " . $stmt->error;
}

$sql = "UPDATE users SET status = ? WHERE id = ?";
$stmt = $mysqli->prepare($sql);
$stmt->bind_param("si", $newStatus, $userId);

if ($stmt->execute()) {
    // 更新成功
} else {
    echo "更新失败: " . $stmt->error;
}

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

if ($stmt ->execute()) {
    // 删除成功
} else {
    echo "删除失败: " . $stmt->error;
}