I need a Query with 2 dynamic values - php

Question

i have an array where i can get id's from a database table, now i need to extract those values as i run a domain link array such as: domain.com/page?id=1
Now this page will bring a category, lets say A category with ID 1 i need to list items under this category on the same database table example products, i can use it without a filter now i need a filter using arrays, here is my code, thank you in advance.
$query ="SELECT * FROM tablename WHERE id = '".$id."' DESC";
before this i have on my php code:
$id = $_GET["id"];
So when i call from this table all comes out, but i need to filter where category 1 (example) have items, not all items with category 2, 3, 4 etc.
With my code i can get the item id as the link with array works fine for example: domain.com/page.php?id=1, but here is the catch, i get item id 1 and i need let's say category id 2, if i run the same link with id=2 i get item id 2 and that's not what i want.
I need to retrieve those values as arrays, any idea? Thank you in advance!
EDITED
Table structure example:
Items
ID, Name, Category
I need Category from Items as a filter like this: domain.com/?id=2&category=2
So i get all items under row Category only

Answer 1

Update your URI to something like this domain.com/page.php?id=1&category=2
$category = $_GET["category"];
$query ="SELECT * FROM tablename WHERE id = '".$id."' AND `Category` = '".$category."'";

Answer 2

Pass the query string parameter optionally
domain.com/page.php?id=1&category=2
Add the where clause dynamically like this
$query ="";
$conact =" where 1=1 ";
if(isset($_GET['id']))
{
$conact.=" and id=".$_GET['id'];
}
if(isset($_GET['category']))
{
$conact.=" and category=".$_GET['category'];
}
$query ="SELECT * FROM tablename $conact DESC";