Question

if i have a category page that im rendering by querying the subcategories in my database, then if i click on one of the subcategories it sends me to

mydomain.com/product_list.php?id=subcategory.

is there a way take the subcategory from the url to query the database to only show the products in that subcategory?

i think it’ll look something like:

$sql = mysql_query("SELECT * FROM products"); 

Answer 1

This can be obtained from $_GET ^DOCs.

$subcategory_id = $_GET['id'];

So this would become:

 if(array_key_exists('id', $_GET) and is_numeric($_GET['id'])) {
     $subcategory_id = (int) $_GET['id'];
     $SQL = "SELECT * FROM products WHERE subcategory_id = $subcategory_id";
 }

Note I have cast the input variable to an integer to prevent SQL injection etc. As the ID must always be a number.

If you need to pass in a string then use mysql_real_escape_string() ^DOCs on it first and don’t type cast to an integer (int):

 if(array_key_exists('id', $_GET)) {
     $subcategory_id = mysql_real_escape_string($_GET['id']);
     $SQL = "SELECT * FROM products WHERE subcategory_id = '$subcategory_id'";
 }