如何在default_scope中指定模型?

How to specify a model in a default_scope?

我的模型Chapterhas_manyPages,而belong_to只有一个Chapter。我正在尝试进行以下连接:

Chapter.joins(:pages)

但是我收到这个错误:

SQLite3::SQLException: ambiguous column name: created_at: SELECT "chapters".* FROM "chapters" INNER JOIN "pages" ON "pages"."chapter_id" = "chapters"."id" AND (created_at >= '2015-04-24 23:22:32.783941')
ActiveRecord::StatementInvalid: SQLite3::SQLException: ambiguous column name: created_at: SELECT "chapters".* FROM "chapters" INNER JOIN "pages" ON "pages"."chapter_id" = "chapters"."id" AND (created_at >= '2015-04-24 23:22:32.783941')

Page 具有以下默认范围:

default_scope { where('created_at >= ?', 7.days.ago) }

没有 default_scope,连接就可以工作。所以我认为我必须以某种方式在 default_scope 中指定 page.created_at。有人知道怎么做吗?

default_scope {
  where("pages.created_at >= ?", 7.days.ago)
}