Rails 2.3: how to handle complex joins without writing custom SQL code

I've looked trough the already asked questions but couldn't find an answer.

I've some models:

Each User can cast many Votes, each Vote is linked to one Post, each Post 开发者_C百科can be linked to many Users. Each User can cast only one vote per post.

class User < ActiveRecord::Base
  has_many :posts, :through => :user_posts
  has_many :user_posts
end

class Vote < ActiveRecord::Base
  belongs_to :user
  belongs_to :post 
end

class Post < ActiveRecord::Base
  has_many :users, :through => :user_posts
  has_many :user_posts, :dependent => :destroy
  has_many :votes, :dependent => :destroy
end

class UserPost < ActiveRecord::Base
  belongs_to :user
  belongs_to :post  
end

What I'm trying to accomplish is to count how many times "User A" has voted for posts that belongs to "User B" in the last day.

I can do this with a full SQL query but I'd like to know if there is an easied "Rails-friendly way" to perform this.

Thanks!

Augusto

Something like this should work

user_a.votes.count(:conditions => { :post => { :users => user_b }, :date => Date.today }, :joins => { :post => :users })