为什么我的PHP没有插入数据库？

Question

我已经对主网页进行了简单的登录。如果用户登录成功，则应将用户名，昵称和日期插入数据库＆＃34; userdata＆＃34;为什么不是这样的？我没有收到任何错误，但我的数据库没有更新并保持空白。

PHP：

<?php
error_reporting(E_ALL & ~E_NOTICE);
session_start();

if($_POST['submit']) {
    $username = strip_tags($_POST['username']);
    $password = strip_tags($_POST['password']);

    $sql = "SELECT id, username, password, nickname FROM users WHERE username = '$username' AND activated = '1' LIMIT 1";
    $connect = mysqli_connect("", "", "", "root_root"); 
    $query = mysqli_query($connect, $sql);

    if ($query) {
        $row = mysqli_fetch_row($query);
        $userId = $row[0];
        $dbUsername = $row[1];
        $dbPassword = $row[2];
        $userLabel = $row[3];
    }


    if ($username == $dbUsername && $password == $dbPassword) {
        $_SESSION['username'] = $username;
        $_SESSION['id'] = $userId;
        $_SESSION['nickname'] = $userLabel;
        $date = date('m/d/y | H:i:s');

        if ($dbPassword == "password") {
            header('Location: firstlogin.php');
        }

        else
        mysqli_query($connect, "INSERT INTO userdata (username, name, timein) VALUES ('$username', '$userLabel', '$date')");
        header('Location: main.php');
        } 
    else {
        $error = "Error: Invalid username or password.";
    }
}
?>