How do I build a query in Ruby on Rails that joins on the max of a has_many relation only and includes a select filter on that relation?

Question

I\'m struggling how to have Ruby on Rails do this query right... in short: to join on a has_many relation but only via the most recent record in that r

Answer 1

+1 to @max's answer.

An alternative though is to add a start_date and end_date attribute to Employment. To get active employees, you can do

Employee
  .joins(:employments)
  .where('end_date is NULL OR ? BETWEEN start_date AND end_date', Date.today)