Rails 2-cases scope

I have scope

scope :for_list, lambda { |brand_ids|
   where('brands.id IN (?)', brand_ids).includes(:models).where("models.popular = '1'").order('mo开发者_如何学编程dels.name')
}

But some times there are no models.popular = 1

And in this case I want to select all from models ignoring popular parameter

How to write that scope?

Since it's simply a lambda function, you can use an if/else in there and it'll get evaluated at the time it's called. Therefore, you could write the scope like this:

scope :for_list, lambda { |brand_ids|
    if self.popular > 1
           where('brands.id IN (?)', brand_ids).includes(:models).where("models.popular = '1'").order('models.name')
    else
           where('brands.id IN (?)', brand_ids).includes(:models).order('models.name')
    end
}

That should work. However, I'd caution against using this. That logic doesn't belong in a scope. Instead, you should question you your views and controllers are set up and rework those.