Question

I’m trying to bind a param to a join via a named scope., but I’m getting an error.

What is the correct way to do that?

class Idea < ActiveRecord::Base

    #relations
    has_many :votes, :inverse_of => :idea
    has_one :has_voted, :class_name => 'Vote', :conditions => ['ip = :ip']

    # named scopes
    scope :with_vote, lambda {|ip| {
        :include => [:has_voted],
        # like this ??
        :conditions => [:has_voted => {:conditions => {:userIp => ip}} ] 
    }}

end

Idea.with_vote(request.ip).all

I believe I need the condition definition in the model for it to appear in the ON clause of a JOIN, rather then in the WHERE one.

---

Edit I’m trying to get the following query

select Ideas.*, Votes.* from Ideas 
left outer join Votes 
on Votes.Idea_id = Idea.id AND Votes.ip = {request.ip}

Answer 1

I do not think you can use incomplete conditions in an association.
If I understand correctly, you need Idea has many votes and votes records the request.ip and idea id.
You want the scope to retrieve all ideas your current request ip voted for.

class Idea
  has_many :votes

  scope :with_vote_from_ip, lambda {|ip| {
    :include => [:votes],
    :conditions => ['votes.ip = ?', ip] 
  }}
end

but if you want all ideas including only votes from current up you need extra conditions on the outer join. I think this is not possible without sql fragment:

class Idea
  has_many :votes

  scope :with_vote_from_ip, lambda {|ip| {
    :joins => 'left outer join Votes on Votes.Idea_id = Idea.id AND Votes.ip = #{ip}' 
  }}
end

now Idea.with_vote_from_ip(request.ip).all should work.