Rails: join with multiple conditions

Question

I have a simple model like

class Interest < ActiveRecord::Base
  has_and_belongs_to_many :user_profiles
end

class UserProfile < ActiveRecord::Base
  h         


        

Answer 1

This will get users that have at least one of the specified interests.

UserProfile.joins(:interests).where(:id => [an_interest_id, another_interest_id])

To get users that have both of the specified interests I'd probably do something like this:

def self.all_with_interests(interest_1, interest_2)
  users_1 = UserProfile.where("interests.id = ?", interest_1.id)
  users_2 = UserProfile.where("interests.id = ?", interest_2.id)

  users_1 & users_2
end

Not amazingly efficient, but it should do what you need?