将简单查询转换为 RoR 中棘手的命名范围

发布于 2024-10-10 21:40:21 字数 440 浏览 5 评论 0原文

我有一个简单的范围界定问题。我想将其作为一个范围：

if article.responses.blank?
      return false
elsif article.responses.last.passed.eql?(false)
      return true
else
   return false
end

因此，在文章模型上，我会有类似这样的内容：

scope :failed_response, {
    :joins=>[:responses],
    :conditions=>["responses.passed = ?", false]
  }

问题是，我只想要最近响应失败的实例。我确信这是一种通过奇特的排序或某种嵌套查询来做到这一点的方法，但我被困住了。谢谢！

原文

I have a simple scoping question. I would like to do this as a scope:

if article.responses.blank?
      return false
elsif article.responses.last.passed.eql?(false)
      return true
else
   return false
end

So on the article model I would have something like this:

scope :failed_response, {
    :joins=>[:responses],
    :conditions=>["responses.passed = ?", false]
  }

The problem is, I only want instances where the most recent response failed. I'm sure these is a way to do this with either fancy sorting or some kind of nested query, but I'm stuck. Thanks!

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酷炫老祖宗 2024-10-17 21:40:21

目前我唯一能想到的是作用域内的子查询：

named_scope :failed_response, {
  :conditions => ["(SELECT passed FROM responses WHERE 
     responses.article_id = articles.id ORDER BY id DESC LIMIT 1) = ?", false]
}

我猜想有某种Rails 方式更好一点或者没有子查询的方式，但我现在想不到。希望这会有所帮助。 :)

The only thing I can think of at the moment is a subquery inside the scope:

named_scope :failed_response, {
  :conditions => ["(SELECT passed FROM responses WHERE 
     responses.article_id = articles.id ORDER BY id DESC LIMIT 1) = ?", false]
}

I guess there is some kind of Rails way that is a bit nicer or a way without a subquery, but I can't think of it at the moment. Hope this helps though. :)

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