Question

I have this method which returns all the categories and groups books belonging to that category

def self.user_categories_list
joins(:books).
select('categories.id, categories.name, count(*) AS books_count').
group('categories.id, categories.name').
order('books_count DESC')
end

Please excuse my question but I am unsure on how to join the users table to get all books belonging to a user by category, or could i do it by book_id belonging to a user?

Any help appreciated

Thanks

Answer 1

I think you should just had a where clause:

def self.user_categories_list(user)
  joins(:books).
  where('books.user_id = ?', user.try(:id) || user).
  select('categories.id, categories.name, count(*) AS books_count').
  group('categories.id, categories.name').
  order('books_count DESC')
end

Note: This code assumes that your Book model has the user_id attribute in its table.