Rails 3.獲取相關模型的屬性

Question

我有兩個模型：註冊和發票。

enrollment belongs to invoice 
invoice has many enrollments 

所以我有這個疑問：@enrollments = Enrollment.where('invoice_id IS NOT NULL')獲得屬於發票全部入學。

但我需要進行某種類型的連接，因爲我真正想要的是具有關聯註冊的發票（id，invoice_number和totals）。

我該怎麼做？

我已經在控制檯到目前爲止已經試過......

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

我得到NoMethodError: undefined method invoice_number for #<Enrollment:0x00000006a1e1a8>，因爲我只能訪問發票編號的。

Answer 1

Invoice.joins(:enrollments).uniq