Ruby on Rails - joins in ruby on rails- ruby on rails tutorial - rails guides - rails tutorial - ruby rails
- joins() allows we to join tables to our current model.
Example
User.joins(:posts)Clicking "Copy Code" button will copy the code into the clipboard - memory. Please paste(Ctrl+V) it in your destination. The code will get pasted. Happy coding from Wikitechy - ruby on rails tutorial - rails guides - ruby rails - rubyonrails - learn ruby on rails - team
- will produce the following SQL query:
"SELECT "users".* FROM "users" INNER JOIN "posts" ON "posts"."user_id" = "users"."id""Clicking "Copy Code" button will copy the code into the clipboard - memory. Please paste(Ctrl+V) it in your destination. The code will get pasted. Happy coding from Wikitechy - ruby on rails tutorial - rails guides - ruby rails - rubyonrails - learn ruby on rails - team
- Having table joined, we will have access to it:
User.joins(:posts).where(posts: { title: "Hello world" })Clicking "Copy Code" button will copy the code into the clipboard - memory. Please paste(Ctrl+V) it in your destination. The code will get pasted. Happy coding from Wikitechy - ruby on rails tutorial - rails guides - ruby rails - rubyonrails - learn ruby on rails - team
Pay attention on plural form. If our relation is :has_many, then the joins() argument should be pluralized. Otherwise, use singular.
Nested joins:
User.joins(posts: :images).where(images: { caption: 'First post' })Clicking "Copy Code" button will copy the code into the clipboard - memory. Please paste(Ctrl+V) it in your destination. The code will get pasted. Happy coding from Wikitechy - ruby on rails tutorial - rails guides - ruby rails - rubyonrails - learn ruby on rails - team
- which will produce:
"SELECT "users".* FROM "users" INNER JOIN "posts" ON "posts"."user_id" = "users"."id" INNER JOIN "images" ON "images"."post_id" = "images"."id""