You cannot have 2 WHERE statements in there;
Code:
$new_products_query = "select distinct p.products_id, p.products_image, p.products_tax_class_id, pd.products_name,
p.products_date_added, p.products_price, p.products_type, p.master_categories_id
from " . TABLE_PRODUCTS . " p, " . TABLE_PRODUCTS_DESCRIPTION . " pd
where p.products_id = pd.products_id
and pd.language_id = '" . (int)$_SESSION['languages_id'] . "'
and p.products_status = 1 WHERE p.master_categories_id = '1'
and p.products_id in (" . $list_of_products . ")";
you want to add a new AND to that existing WHERE if you are trying to limit the Products to be those coming just from Products using master_categories_id 1 with:
Code:
$new_products_query = "select distinct p.products_id, p.products_image, p.products_tax_class_id, pd.products_name,
p.products_date_added, p.products_price, p.products_type, p.master_categories_id
from " . TABLE_PRODUCTS . " p, " . TABLE_PRODUCTS_DESCRIPTION . " pd
where p.products_id = pd.products_id
and pd.language_id = '" . (int)$_SESSION['languages_id'] . "'
and p.products_status = 1
and p.master_categories_id = '1'
and p.products_id in (" . $list_of_products . ")";