Has_many through query - ruby-on-rails

Question

I have 2 models (Books and Authors) and a third table joining them (has_many through association).
I am trying to implement search in my app and run a query on both tables. My query looks like this and I cannot figure out the problem:
Book.includes(:authors, :author_books).where("books.title LIKE ? OR authors.name = LIKE ?", "%#{book}%", "%#{book}%")
This is the error that I get running it:
PG::UndefinedTable: ERROR: missing FROM-clause entry for table "authors"
SELECT "books".* FROM "books" WHERE (books.title LIKE '%Harry%' OR authors.name = LIKE '%Harry%')
Here is my schema of the three tables:
create_table "author_books", force: :cascade do |t|
t.bigint "author_id"
t.bigint "book_id"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
t.index ["author_id"], name: "index_author_books_on_author_id"
t.index ["book_id"], name: "index_author_books_on_book_id"
end
create_table "authors", force: :cascade do |t|
t.string "name"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
create_table "books", force: :cascade do |t|
t.string "title"
t.text "description"
t.string "image"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
t.integer "rating"
t.string "critics"
t.float "price"
end
author_book.rb
class AuthorBook < ApplicationRecord
validates_presence_of :author, :book
belongs_to :author
belongs_to :book
end
author.rb
class Author < ApplicationRecord
validates :name, uniqueness: true
has_many :author_book
has_many :books, through: :author_book
end
book.rb
class Book < ApplicationRecord
validates :title, uniqueness: true, :case_sensitive => false
has_many :author_book
has_many :authors, through: :author_book
has_many :categories, through: :category_book
def self.search_book(book)
if book
Book.joins(:authors, :author_books).includes(:authors, :author_books).where("books.title LIKE ? OR authors.name = LIKE ?", "%#{book}%", "%#{book}%")
end
end
end
I call this search_book method in my book controller like so:
def search
#books = Book.search_book(params[:book])
end
Some help, please?
Thanks!

Answer 1

From the docs
If you want to add conditions to your included models you’ll have to
explicitly reference them.
That said, you need to add references(:authors) to your query like below to resolve the error
Book.includes(:authors, :author_books).where("books.title LIKE ? OR authors.name = LIKE ?", "%#{book}%", "%#{book}%").references(:authors)
Update:
Can't join 'Book' to association named 'author_books'; perhaps you
misspelled it?
You should replace has_many :author_book with has_many :author_books and through: :author_book with through: :author_books

Answer 2

You forgot to join authors and author_books to your relation. includes loads both :author and :author_books but in separate queries.
Try this:
Book.joins(:authors, :author_books).includes(:authors, :author_books).where("books.title LIKE ? OR authors.name = LIKE ?", "%#{book}%", "%#{book}%")