Question

除了最明显的事情之外，我真的很喜欢Rails的发现者。当事情变得比

更先进时，我总是求助于SQL

Model.find(:all, :conditions => ['field>? and field<? and id in (select id from table)', 1,2])

我有这个方法：

def self.get_first_validation_answer(id)
a=find_by_sql("
  select answers.*, answers_registrations.answer_text
  from answers_registrations left join answers on answers_registrations.answer_id=answers.id
  where 
    (answers_registrations.question_id in (select id from questions where validation_question=true)) 
    and
    (sale_registration_id=#{id})
  limit 1
").first

a.answer_text || a.text if a
end

有人可以创建一个让我得到我想要的发现方法吗？

此致

雅各

Answer 1

class AnswersRegistration < ActiveRecord::Base
  has_many :answers
end

id = 123
the_reg = AnswersRegistration.first(
  :joins => :answers, 
  :conditions => '(question_id in (select id from questions where validation_question = true)) and (sale_registration_id = ?)', id)

（未测试的）

Answer 2

如果满足您的需要，只需使用binarylogic的Searchlogic gem。在这里：http://github.com/binarylogic/searchlogic

Answer 3

有时AR会在复杂的嵌套条件下窒息，但理论上你应该能够做到这一点：

AnswersRegistration.first(:conditions => { :question => { :validation_question => true },
                                           :sale_registration_id => id },
                          :include => :answer)

Rails中的高级查找

3 个答案: