哪里查询具有唯一性

Question

我想查询正确=真的答案，如果他们有相同的问题ID，只抓一个答案。我尝试的是uniq或者不同。

@answers = Answer.where(id: params[:answer_ids])
@correct_answers = @answers.where(correct: true, question_id: distinct).count

你怎么能用同样的问题_id获得任何答案的答案？

Answer 1

试试这个：

@answers = Answer.joins(:question).where(id: params[:answer_ids])
@correct_answers = @answers.where(correct: true).distinct(:question_id)