无效的Active Record Statement Rails 2.3.16

Question

我正在使用Rails 2.3.16，Ruby 1.8.7

对于以下代码行，我得到如下错误：

代码：

ForeignScheduledItem.find(:all, 
                          :conditions => { :foreign_scheduled_item => 
                                           { :scheduled_items => { :subscription_id => params[:subscription_id] } } }, 
                          :joins => :scheduled_item).each { |i| @subscriptions.push(Subscription.find_by_id(i.subscription_id)) }

错误：

ActiveRecord::StatementInvalid (ActiveRecord::StatementInvalid):
  app/controllers/api/cache_controller.rb:47:in `expire_day_event_sets'
  config/initializers/restfulx.rb:18:in `call'
  config/initializers/restfulx.rb:38:in `call'
  /home/ranjit/.rvm/rubies/ruby-1.8.7-p374/lib/ruby/1.8/webrick/httpserver.rb:104:in `service'
  /home/ranjit/.rvm/rubies/ruby-1.8.7-p374/lib/ruby/1.8/webrick/httpserver.rb:65:in `run'
  /home/ranjit/.rvm/rubies/ruby-1.8.7-p374/lib/ruby/1.8/webrick/server.rb:173:in `start_thread'
  /home/ranjit/.rvm/rubies/ruby-1.8.7-p374/lib/ruby/1.8/webrick/server.rb:162:in `start'
  /home/ranjit/.rvm/rubies/ruby-1.8.7-p374/lib/ruby/1.8/webrick/server.rb:162:in `start_thread'
  /home/ranjit/.rvm/rubies/ruby-1.8.7-p374/lib/ruby/1.8/webrick/server.rb:95:in `start'
  /home/ranjit/.rvm/rubies/ruby-1.8.7-p374/lib/ruby/1.8/webrick/server.rb:92:in `each'
  /home/ranjit/.rvm/rubies/ruby-1.8.7-p374/lib/ruby/1.8/webrick/server.rb:92:in `start'
  /home/ranjit/.rvm/rubies/ruby-1.8.7-p374/lib/ruby/1.8/webrick/server.rb:23:in `start'
  /home/ranjit/.rvm/rubies/ruby-1.8.7-p374/lib/ruby/1.8/webrick/server.rb:82:in `start'

请你帮忙。