每当有人转到sql中的链接时，如何在mysql数据库中为int添加1

Question

I have tested everything and nothing works here's my code

<?php
session_start();
if (!isset($_GET['id']) || !is_numeric($_GET['id'])) { die('Invalid id'); }
$conn = mysqli_connect("redacted", "redacted", "redacted", "redacted");
if (!$conn) {
    die("Connection failed: ".mysqli_connect_error());
}
$url = "http://".$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI'];
$id = (int)$_GET['id'];
"UPDATE affiliate SET clicks WHERE ID='$id' = clicks + 1";
header("Location: https://discord.gg/CjzZRBq");
?>

and after I want it to echo on the users dashboard this is what I have

<h1>Clicks</h1>
                <br />
                <br />
                You have gotten: <?php $conn = mysqli_connect("localhost", 
"id2278622_jonny", "Fencing1", "id2278622_affiliate");
 if (!$conn) {
    die("Connection failed: ".mysqli_connect_error());
}
$sql = "SELECT clicks FROM affiliate WHERE ID='$ID'";
echo "$sql";
?> Clicks!

but it just echos the sql code

Answer 1

You haven't actually sent your query to the database. You've just built a query string. A string that you didn't even save to a variable.

$id = (int)$_GET['id'];
"UPDATE affiliate SET clicks WHERE ID='$id' = clicks + 1";
header("Location: https://discord.gg/CjzZRBq");

Should be:

$id = (int)$_GET['id'];
$qry= "UPDATE affiliate SET clicks = clicks+1 WHERE ID='$id'";
conn->query($qry);
header("Location: https://discord.gg/CjzZRBq");

---

You should also look up SQL Injection. Casting to an int mitigates risk, but you should definitely be using bind variables.