在两个表之间添加 JOIN [英] Adding a JOIN between two tables

问题描述

这是我的课程:

Model Organization
has_many Students

Model Student
has_many Classes
belongs_to Organization

Model Class
a field named : price
belongs_to Student
scope :top_expensive_classes, joins(:students).order('price DESC')

现在我要列出最昂贵的 10 个课程

至少我遇到的第一个问题是，在 params 中，我有 organization_id 可以根据它进行过滤，但是我像这样编写控制器，但它不起作用，因为它认为它应该在 Class 模型中找到 organization_id 但它在 Student 模型中.

At least the first problem I have is that in the params I have the organization_id to filter based on that But I write my controller like this which does NOT work because it thinks it should find organization_id in the Class model but it is in the Student model.

@results = Class.top_expensive_classes.where(organization_id: params[:id]).limit(RESULT_SET_COUNT)

所以我想知道是否有办法解决这个问题?我想我应该在某个地方引入一个新的连接?但想不通.

So I was wondering if there is a way to fix this? I think I should introduce a new join somewhere? but couldn't figure it out.

推荐答案

你的范围中有一个错字:joins:(:programs) 应该是 joins(:programs)

There's a typo in your scope: joins:(:programs) should be joins(:programs)

要根据 Student 中的组织 ID 进行提取，您可以这样做:

To fetch based on the organization id in Student you may be able to do this:

@results = Class.top_expensive_classes
  .joins(student: :organization)
  .where(organization: {id: params[:id]})

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