Question

在has_many直通查询中遇到一些问题。

使用此处的示例：http://guides.rubyonrails.org/association_basics.html#the-has_many-through-association

class Physician < ActiveRecord::Base
  has_many :appointments
  has_many :patients, :through => :appointments
end

class Appointment < ActiveRecord::Base
  belongs_to :physician
  belongs_to :patient
end

class Patient < ActiveRecord::Base
  has_many :appointments
  has_many :physicians, :through => :appointments
end

约会表有一个名为 appointment_date

的列

如何让特定医生的所有患者在指定日期预约？

Answer 1

Patient.includes(:physicians, :appointments).where('physicians.id = ? AND appointments.appointment_date = ?', <id or ids array>, Date.today)

Date.today可以用任何东西改变，而pysician由id或id数组指定。

你也可以这样做：

physician = Physician.find(id)
patients = physician.patients.includes(:appointments).where('appointments.appointment_date  = ?', some_date)

编辑：

在Rails 4和转发中，您需要将references(:appointments)添加到查询中，以便在where子句中使用约会。

Rails has_many通过查询取决于through表属性

1 个答案: