如何左加入细节？

Question

我有模型 Customer、CustomerQuestion 和 CustomerAnswer。

Customer has_many CustomerQuestion

Customer has_many CustomerAnswer

CustomerQuestion has_one CustomerAnswer

当我调用 Customer 时，我可以获得详细的 CustomerAnswer，但我想按 CustomerQuestion 中的字段进行排序。我将如何离开加入 CustomerQuestion 到 CustomerAnswer 以供我订购？

我的示例代码，但我不知道下一步该做什么；

@customer = Customer.find(params[:id])
@customer.customer_answers.join("LEFT JOIN customer_questions cq ON cq.id = customer_answers.customer_question_id ").order("ISNULL(cq.order_by), customer_answers.id")

Answer 1

@customer = Customer.find(params[:id])
@customer_answers = @customer.customer_answers.includes(:customer_question).order(id: :desc)

或者您可以只粘贴第 2 行的代码以共享每个迭代器。