Rails，由嵌套项选择

Question

class Client < ActiveRecord::Base
 attr_accessible :name
 has_many :comments, :dependent => :destroy
end

class Comment < ActiveRecord::Base
 attr_accessible :title, :date
 belongs_to :client
end

如何按评论日期查找所有客户＆＃39; 2012-01-30＆＃39;？

Answer 1

假设date是日期类型字段

Client.joins(:comments).where(comments: { date: Date.new(2012,1,30) })