How to query to get all users based on a nested resource?

Given:

Room (id, updated_at)
RoomMember (room开发者_开发百科_id, user_id)
User (id)

In rails how can I get all users that belong to all rooms that were last updated_at in the past 24 hours?

Thanks

User.select('distinct users.*').joins(:rooms).where('rooms.updated_at > ?', 1.day.ago)

Assuming your models are as follows:

class User
  has_many :room_members
  has_many :rooms, :through => :room_members
end

class RoomMember
  belongs_to :user
  belongs_to :room
end

class Room
  has_many :room_members
  has_many :users, :through => :room_members
end

You can use the following:

User.all(:select => "DISTINCT users.*",
   :joins => :rooms, :conditions => ["rooms.updated_at >=", 1.day.ago])