Keep Coding

I have the following associations set up
class bookinghdr
belongs_to :agent
end
class bookingitem
belongs_to :bookinghdr, :include => agent
end
So I was expecting to be able to do the following:
named_scope :prepay, :include=>["bookinghdr"], :conditions => ["bookinghdr.agent.agenttype = 'PP'"]
and in my controller do:
b = Bookingitem.prepay
But that gives me a ActiveRecord::StatementInvalid: Mysql::Error: Unknown column 'bookinghdr.agent.agenttype'
However if I don't include the conditions clause then I get a recordset on which I can do:
b = Bookingitem.prepay
b[0].bookinghdr.agent.agenttype
without any error!!
I don't want to have to get all the records and then iterate over them to find the ones whose agent has a 'PP# flag. I was hoping that AR would do that for me.
Anybody got any ideas on how to achieve this?
Thanks in advance.
Purvez

Your question shows that you have not yet fully understood how associations and named scopes work. Since I cannot tell from your question what parts aren't clear, I suggest you read the Association Basics guide at http://guides.rubyonrails.org/v2.3.11/association_basics.html. This should bring you up to speed regarding the concepts you want to implement. After you have read the guide it should all make sense.