ruby-on-rails - Rails 3 - 从相关模型中获取和排序模型对象

Question

我有 2 个模型，Teacher和TeacherLeader：

#  id        :integer
#  last_name :string(255)
class Teacher < ActiveRecord::Base 
  has_one :teacher_leader
end

#  teacher_id :integer
class TeacherLeader < ActiveRecord::Base  
  belongs_to :teacher
end

我想找到所有担任教师领导的教师，并通过last_name. 我怎样才能做到这一点？

Answer 1

Teacher.joins(:teacher_leader).uniq.order(:last_name)