ActiveRecord#Base.includes

pry(main)> @books = Book.includes(:bookmarks, :reviews).order('updated_at DESC')
  Book Load (3.2ms)  SELECT "books".* FROM "books"  ORDER BY updated_at DESC
  Bookmark Load (4.9ms)  SELECT "bookmarks".* FROM "bookmarks" WHERE "bookmarks"."book_id" IN (3, 2)
  Review Load (0.2ms)  SELECT "reviews".* FROM "reviews" WHERE "reviews"."book_id" IN (3, 2)

@books.to_sql
=> "SELECT \"books\".* FROM \"books\"  ORDER BY updated_at DESC"

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