Hide specific products or products from a category from homepage

[axafarm]

Hello,

 

I want to hide specific products or products from a specific category from homepage. I have sections like new products, best seller, or featured products on homepage and I want to hide the products from a category to appear in those sections. I know how to identify the products from that category by reference, all the products from that category starts with the same reference. I identify the products with this code:  {if substr($product.reference, 0, 1) =='W'}, the code works because I used it to set an default image to products with 'W' reference. Now I don't know how to make it work so I can hide products from homepage that starts with reference 'w' for example. I want to hide them only from homepage. Please help me!

 

Thank you!

[NemoPS]

In category.php, getProducts method, you can add this condition to the sql that retrieves products. Make sure it's in the WHERE part
Replace 2 with the homepage id.

'.($this->id == 2 ? 'AND p.id_reference !="whatever"' : "").'

You can obviously add different conditions to check what part of the reference to check

[axafarm]

So basically I have to add here in this code 

if ($getTotal) {
            $sql = 'SELECT COUNT(cp.`id_product`) AS total
                    FROM `' . _DB_PREFIX_ . 'product` p
                    ' . Shop::addSqlAssociation('product', 'p') . '
                    LEFT JOIN `' . _DB_PREFIX_ . 'category_product` cp ON p.`id_product` = cp.`id_product`
                    WHERE cp.`id_category` = ' . (int) $this->id .
                ($front ? ' AND product_shop.`visibility` IN ("both", "catalog")' : '') .
                ($active ? ' AND product_shop.`active` = 1' : '') .
                ($idSupplier ? 'AND p.id_supplier = ' . (int) $idSupplier : '');

            return (int) Db::getInstance(_PS_USE_SQL_SLAVE_)->getValue($sql);
        }

I'm using prestashop 1.7.5, my homepage doesn't have an ID in link, if there is an ID for homepage I really don't know how to find it..