PHP$\u无法工作。尝试从用户表中获取，然后在后续表中发布

使用$\u GET id尝试获取我试图遵循的用户id，然后将其发布到下表中，这是不起作用的。但是，如果我能够将loggedin users id发布到同一表中的相邻字段中，则无法执行此操作

这是我试图填充的mysql表

<?php
require_once("../../config.php");
include("../../classes/User.php");

if( isset($_SESSION['userLoggedIn']) && $_GET['id'] ) {
    $userLoggedIn = new User($con, $_SESSION['userLoggedIn']);

    if( !$database->has('follows', ['AND' => ['followFrom' =>      $userLoggedIn->id, 'followTo' => $_GET['id'] ]]) ) {
        $database->insert('follows', [
            'followFrom' => $userLoggedIn->id,
            'followTo' => $_GET['id']
        ]);
        echo 'followed';
    } else {
        $database->delete('follows', ['AND' => ['followFrom' => $userLoggedIn->id, 'followTo' => $_GET['id'] ]]);
        echo 'unfollowed';
    }

}
?>

希望我单击要跟踪的用户id被发布到要跟踪的字段，以便跟踪表

    <?php
require_once("../../config.php");
include("../../classes/User.php");

if( isset($_SESSION['userLoggedIn']) && **isset($_GET['id'])** ) {
    $userLoggedIn = new User($con, $_SESSION['userLoggedIn']);

    if( !$database->has('follows', ['AND' => ['followFrom' =>      $userLoggedIn->id, 'followTo' => $_GET['id'] ]]) ) {
        $database->insert('follows', [
            'followFrom' => $userLoggedIn->id,
            'followTo' => $_GET['id']
        ]);
        echo 'followed';
    } else {
        $database->delete('follows', ['AND' => ['followFrom' => $userLoggedIn->id, 'followTo' => $_GET['id'] ]]);
        echo 'unfollowed';
    }

}
?>

我想你错过了isset的功能