Question

我尝试根据关联值添加范围。

我有两个班级：

class Question < ActiveRecord::Base

  has_many :quiz_questions

  scope :entro,     -> { where 'quiz_type = ?', 'base' }
  scope :oltre,     -> { where 'quiz_type = ?', 'oltre' }

end

class QuizQuestion < ActiveRecord::Base
  belongs_to :question

  scope :errors,     -> { where 'correct = ?', false }
  scope :no_errors,     -> { where 'correct = ?', true }
end

我用

self.quiz_questions.merge(Question.entro)

我有这个错误。

PG::UndefinedColumn: ERROR:  column "quiz_type" does not exist
LINE 1: ...ions"  WHERE "quiz_questions"."quiz_id" = $1 AND (quiz_type ...
                                                             ^
: SELECT "quiz_questions".* FROM "quiz_questions"  WHERE "quiz_questions"."quiz_id" = $1 AND (quiz_type = 'base')

我只需要从一系列测验问题中计算我的收藏中有多少问题{ where 'quiz_type = ?', 'base' }。

更新

QuizQuestion是Quiz类和Question Class之间的连接表。我简化了课程。

顺便说一句，quiz_questions集合是这样的：

#<QuizQuestion id: 12436, quiz_id: 315, question_id: 253, created_at: "2014-11-07 13:06:18", updated_at: "2014-11-07 13:11:10", solution: 1575, correct: true>,
 #<QuizQuestion id: 12437, quiz_id: 315, question_id: 538, created_at: "2014-11-07 13:06:18", updated_at: "2014-11-07 13:11:10", solution: 2429, correct: true>,
 #<QuizQuestion id: 12441, quiz_id: 315, question_id: 395, created_at: "2014-11-07 13:06:18", updated_at: "2014-11-07 13:11:10", solution: 1999, correct: true>,

我在联接表中使用一个字段来标记用户是否已回答问题的权利。

quiz_questions.errors.count给我总错误。我现在需要按类型对总错误进行分组，并且quiz_type字段位于相关的问题模型中。

Answer 1

尝试更新范围以使用散列样式，这样可确保将列转换为"questions"."quiz_type"而不是使用quiz_type。它可能会修复它，你可能必须加入而不是合并，如果它不能解决它

scope :entro,     -> { where quiz_type: 'base' }
scope :oltre,     -> { where quiz_type: 'oltre' }

Answer 2

我找到了解决方案

quiz_questions.joins(:question).merge(Question.entro)

关联值的Activerecord范围

2 个答案: