Using Named Scopes Across Models with ActiveRecord#Merge Discussion

You have to fix your latest blog Post excerpt on the home page.
Great site btw.

I am doing it with subquery
Like

Author.where(id: Book.available.select(:author_id))

I agree that your version is cleaner and easier to remember,
but you might want to add .distinct after joins to avoid duplicated authors.

Well, this is useful, but ugly... Thinking about querying, im not supposed to "merge" anything. IMHO

My wish was Author.books.scope(:available), lol

Minor nitpick: but I really think you mean `ActiveRecord::Relation#merge`, not `ActiveRecord#merge`

(Y)

Something wrong with the video :/

great! is ugly, but useful, thanks!

Big thanks! Had a default scope on my Model but rails 4.2.5 didn't unscope it when I was doing "each do" so using the .joins(:model).merge(Model.scope) you suggested instead

Could do something like:

scope :has_available_books, -> { joins(:books).merge(Book.available) }

Then you could just do:

Author.has_available_books

Need to note that merges on the same attribute overrides each other.

class Book < ActiveRecord::Base
...
scope :red, ->{ where(color: "red") }
scope :green, ->{ where(color: "green") }
end

Author.joins(:books).merge(Book.red).merge(Book.green)
^ would apply only green, because overwrite previous merge