How can use an ID a table in another table value?

Question

I'm trying to search in table policy_logs if it has a pdf.

Here my tables:

|policies|
  |id|  |name|
    1     abc
    2     def
    3     ghi

|policy_logs|
  |id|  |name| |policy_id|
    1   ab.pdf   1
    2   cd.pdf   1
    3   ef.pdf   3
    4   ij.pdf   3   

I'm trying to use all the column policy_id from policy_logs like "id" IN policies table

Here my controller:

@pdf =  PolicyLog.find(:all,:select=>['policy_id as pdf'],:group=>['policy_id'])
@policy = Policy.find(:all,:conditions=>['id IN (?)',@pdf ])

Here my models:

class Policy < ActiveRecord::Base
   has_many :policy_logs
end

class PolicyLog < ActiveRecord::Base
   belongs_to :policy
end

Here my view:

<%  @policy.each do |p|  %>
   <%= p.id %>
   <%= p.name %>
<% end %>

This is want I want like result

  |id|  |policy_id|
    1      1
    3      3

I tried this but is getting NULL values:

@pdf =  PolicyLog.find(:all,:select=>['policy_id as pdf'],:group=>['policy_id'])
@policy = Policy.find(:all,:conditions=>['id IN (?)',@pdf ])

Here is the log:

SELECT policy_id as pdf FROM `policy_logs` GROUP BY policy_id
SELECT * FROM `policies` WHERE (id IN (NULL),(NULL),(NULL),(NULL))

Also tried using array 0:

@pdf =  PolicyLog.find(:all,:select=>['policy_id as pdf'],:group=>['policy_id'])
@policy = Policy.find(:all,:conditions=>['id IN (?)',@pdf[0].pdf ])

But I got only one result, here is the log:

SELECT policy_id as pdf FROM `policy_logs` GROUP BY policy_id
SELECT * FROM `policies` WHERE (id IN (1))

Also tried using array 1:

@pdf =  PolicyLog.find(:all,:select=>['policy_id as pdf'],:group=>['policy_id'])
@policy = Policy.find(:all,:conditions=>['id IN (?)',@pdf[1].pdf ])

But I got only one result, here is the log:

SELECT policy_id as pdf FROM `policy_logs` GROUP BY policy_id
SELECT * FROM `policies` WHERE (id IN (3))

And Finally i tried

@pdf= PolicyLog.find(:all,:select=>['policy_id as pdf'],:group=>['policy_id'])
@search= Policy.find(:all,:conditions=>['id IN (?)',@pdf.each do |a| { a.pdf} ])

But i got

odd number list for Hash.
unexpected ']', expecting kEND

Maybe there are others ways to search it.

Please somebody can help me, please?

Answer 1

Try like this:

@search = Policy.find(:all,:conditions => {:id => @pdf.map{|p| p.pdf})

Or:

@search = Policy.find(:all,:conditions => {:id => @pdf})