Ruby on Rails 3中，如何解决出现未知密钥：begin_date的ArgumentError问题？

本文共计251个文字，预计阅读时间需要2分钟。

我有许多具有较高资历的免费对象。我想查询是否有特定日期范围内的免费对象：def has_current_membership(memberships, begin_date, end_date): memberships.count(begin_date=:begin_date AND end_date=:end_date, { :begin_date=> Time.now.beginning_of_day })

我有一个具有很多会员资格的豁免对象.我想弄清楚豁免是否有特定季度的会员资格：

def has_current_membership? memberships.count("begin_date >= :begin_date AND end_date <= :end_date", { :begin_date => Time.now.beginning_of_quarter, :end_date => Time.now.end_of_quarter }).count > 0 end

然而,这给了我ArgumentError：未知密钥：begin_date.但是,成员资格有一个begin_date列,因为如果我在控制台中执行Waiver.first.memberships,我会得到：

[#<Membership id: 20, waiver_id: 1, begin_date: "2011-10-01", end_date: "2012-01-01", created_at: "2011-11-19 07:10:10", updated_at: "2011-11-19 07:10:10">]

我究竟做错了什么？

您应该使用.where作为查找条件,而不是.count两次：

memberships.where("begin_date >= :begin_date AND end_date <= :end_date", { :begin_date => Time.now.beginning_of_quarter, :end_date => Time.now.end_of_quarter }).count > 0