Rails where condition on has_and_belongs_to_many association

Question

I have a has_and_belongs_to_many association between product and supplier.

join table is products_suppliers.

I am trying to create dependent selects in a form so that when I select a supplier, in the product dropdown only corresponding products appears.

I'm having a problem with the where conditions.

If I was in a situation where product belongs_to supplier I would do:

 @products = Product.where("supplier_id = ?", params[:supplier_id])

How do I achieve the same in a has_and_belongs_to_many association?

Answer 1

Use this code:

supplier = Supplier.find_by(supplier_id: params[:supplier_id])
@products =supplier.products if supplier.present?