Rails 3. get attribute of related model

Question

I have two models: Enrollment and Invoice.

enrollment belongs to invoice
invoice has many enrollments

So I have this query: @enrollments = Enrollment.where('invoice_id IS NOT NULL') to get all enrollments that belong to an invoice.

But I need to make some type of join because what I really want is the invoices (id, invoice_number and totals) that have enrollments associated.

How can I do that?

What I have tried so far in the console...

enrollments = Enrollment.where('invoice_id IS NOT NULL').joins(:invoice)
enrollments.each do |enrollment|
  puts enrollment.invoice_number
end

I get NoMethodError: undefined method invoice_number for #<Enrollment:0x00000006a1e1a8> because I can only access the id's of the invoices.

Answer 1

Invoice.joins(:enrollments).uniq