Ruby on Rails条件损坏

问题描述

我有Ruby on Rails2.3.x.我有一个用于学习管理系统的数据库.

I have Ruby on Rails 2.3.x. I have a database for a learning management system.

为用户提供了一个用户ID，并进行测验.如果用户参加任何测验，我希望显示平均分数.分数在quiz_results表中以0到1之间的浮点数形式列出，因此在* 100和.round之间也有一个user_id行.但是，如果用户没有进行任何测验，我希望显示"No quizzes taken".

Users are given a user ID, and take quizzes. If a user takes any number of quizzes, I want the average score to display. The score is listed in the quiz_results table as a float between 0 and 1, hence the * 100 and .round, with a user_id row as well. But if a user hasn't taken any quizzes, I want "No quizzes taken" to appear.

代码如下:

-if QuizResult.find_by_user_id(@user_id).present?
    ="#{(QuizResult.average('score', :conditions => 'user_id = #{@user.id}') * 100).round}%"
-else
    %em No quizzes taken

问题是，无论如何，即使有quiz_results条目，也会出现"No quizzes taken".

The problem is that no matter what, even if there is a quiz_results entry, the "No quizzes taken" still appears.

我在做什么错了?

推荐答案

您正在测试是否:

QuizResult.find_by_user_id(@user_id)

存在，但我怀疑您的意思是

exists, but I suspect you meant:

QuizResult.find_by_user_id(@user.id)

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