ExtendedJoinsImpl

Syntactic sugar for using a subquery and left outer join in ActiveRecord

Installation

Add this line to your application's Gemfile:

gem 'extended_joins_impl'

And then execute:

$ bundle

Or install it yourself as:

$ gem install extended_joins_impl

Usage

In these case

class User < ActiveRecord::Base
  belongs_to :type
  has_many :user_notes,
           class_name: "Note",
           primary_key: :code,
           foreign_key: :user_code

end

class Type < ActiveRecord::Base
end

class Note < ActiveRecord::Base
end

# SELECT users.* FROM users INNER JOIN (SELECT * FROM types) types ON users.type_id = types.id
User.scoped.extended_joins(:inner, Type.scoped)

# SELECT users.* FROM users LEFT OUTER JOIN (SELECT * FROM types) types ON users.type_id = types.id
User.scoped.extended_joins(:outer, Type.scoped)

# SELECT users.* FROM users INNER JOIN (SELECT * FROM types WHERE id = 3) types ON users.type_id = types.id
User.scoped.extended_joins(:inner, Type.where(id: 3))

# SELECT users.* FROM users INNER JOIN (SELECT * FROM types) user_types ON users.type_id = user_types.id
User.scoped.extended_joins(:inner, Type.scoped, as: "user_types")

# SELECT users.* FROM users INNER JOIN (SELECT * FROM notes) notes ON users.code = notes.user_code
User.scoped.extended_joins(:inner, Note.scoped, on: {code: :user_code})

# SELECT users.* FROM users INNER JOIN (SELECT * FROM notes) notes ON users.id = notes.user_id AND notes.user_code = 3
User.scoped.extended_joins(:inner, Note.scoped, where: {user_code: 3})

# if alias name is same as association name
# SELECT users.* FROM users INNER JOIN (SELECT * FROM notes) notes ON users.code = notes.user_code
User.scoped.extended_joins(:inner, Note.scoped, as: "user_notes")

Contributing

1. Fork it ( http://github.com//extended_joins_impl/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request