如何使用用户登录信息在 PHP 和 MySQL 查询中创建 IF ELSE 条件

Question

我正在创建一个带有单个 index.php 文件的网站，其中包含 2 个标头。我正在使用“include”语句来在索引上调用标头。“header1.php”是网站访客的默认标头，其中还包含“登录”按钮。而“header2.php”是那些已登录其帐户并具有“注销”按钮的标题。问题是，当访客访问网站时，网站将显示默认标头“header1.php”。当用户登录他/她的帐户时，将显示“header2.php”。我应该如何调用标题？if else 语句中应该写什么条件？它可能需要访问 MySQL 数据库来获取用户数据。例子：<?phpif( user log in to his account ){    include 'header2.php';}else{    include 'header1.php';}我的登录脚本是：<?phpsession_start();$username = $_POST['username'];$password = $_POST['password'];$connect = mysqli_connect("localhost", "root", "", "yfcgk_canlaon");$query = mysqli_query($connect, "SELECT * from members WHERE USERNAME = '$username' and PASSWORD = '$password'");$count = mysqli_num_rows($query);if($count <= 0 ){    session_start();    header("location:index.php?error");}else{    $_SESSION['user'] = 1;    $_SESSION['username'] = ucwords($username);    header("location:index.php");}?>

Answer 1

可能是这个

if ($_SESSION['user'] && $_SESSION['user'] == 1) {

  include 'header2.php';

}else{

  include 'header1.php';

}