Ruby has_many與Postgres數據庫相關的模型查詢（Rails 5）

Question

我有模型，醫師，has_many患者。嘗試寫一個查詢，只會導致醫生擁有所有治癒的患者。因此，每位醫師患者必須具有「is_cured：true」的屬性（或者對於所有內科醫生患者至少不是零）。

有這到目前爲止，但醫生們表示只是有一個治癒病人，不是所有的時候了：

@physicians = Physician.includes(:patients) .where.not(patients: { id: nil }) .where(patients: { is_cured: true })

型號：

class Physician < ApplicationRecord 
    has_many :patients 
    has_many :recommendations, through: :patients 
end 

class Patient < ApplicationRecord 
    belongs_to :physician 
    belongs_to :recommendation 
end 

class Recommendation < ApplicationRecord 
    has_many :patients 
    has_many :physicians, through: :patients 
end 

感謝您能給任何幫助！

Answer 1

# Fetches physicians who have at-least one uncured patient 
phys_with_uncured_patients = Physician.joins(:patients).where(patients: { is_cured: false }) 

#Fetches physicians who have at-least one patient and all are cured. 
Physician.joins(:patients).where.not(id: phys_with_uncured_patients) 

Answer 2

physician_ids = Patient.where(is_cured: false).pluck(:physician_id) 

Physician.joins(:patients).where.not(id: physician_ids)