get discount_id

Hi dear
I need get product discount_id from #__hikashop_discount table in database.
how can get discount_id a product use which discount?
thank you

Thank you dear Jerome
My discount apply on a single product and I create many discount and a single product use a one discount.
now I need get discount_id for each product. how can get it?

I use this code and its work now

$product_id =  (int)trim( $params->get('product_id') );
$query="SELECT discount_percent_amount,discount_flat_amount FROM `#__hikashop_discount` WHERE discount_product_id=$product_id";