has_many and No method error issue

Question

I have two tables: Stores and products. The store model has a has_many :products and the products has a belongs_to :store

I\'m trying to do

Answer 1

You have it backwards. Since you can have many stores, Rails will not return all the products where open: true.

You need to join and lookup the products where the store is open.

Product.joins(:store).where(store: {open: true}).where("created_at <= ?", 1.month.ago)

Answer 2

Not a very easy thing to do - products is a method defined on an instance of Store and you are calling it on the relation. I would probably go with:

Product.where(store_id: Store.where(open:true).pluck(:id)).where("created_at <= ?", 1.month.ago)

which would generate two db calls, but also returns a clean and easy to query scope. Another approach would be to use join:

Product.joins(:store).where(store: { open: true }).where("created_at <= ?", 1.month.ago)

This will do the work with one query, but due to the join it won't be that easy to manipulate the resulting scope that easily.