为什么我定义的范围不起作用？ 我的代码的一部分如下：
users habtm messages
projects habtm messages
Message.rb
scope :new_messages,-> { where(msg_status: 'new') }
scope :without_project,-> { includes(:messages_projects).where('messages_projects.project_id' => nil) } #<---this one
def mymethod
new_messages = Message.new_messages
@users = User.active.joins(:messages).merge(Message.new_messages).uniq
@users.each do |user|
new_users_messages = new_messages.without_projects.includes(:messages_users).where('messages_users.user_id' => user.id)
end
end
但如果我直接进行查询，则可以：
new_users_messages = new_messages.includes(:messages_projects).where('messages_projects.project_id' => nil).includes(:messages_users).where('messages_users.user_id' => user.id)
有人可以向我解释为什么会这样吗？
更新 这是日志，但没有什么有趣的
User Load (20.0ms) SELECT DISTINCT "users".* FROM "users" INNER JOIN "accounts" ON "accounts"."user_id" = "users"."id" INNER JOIN "messages_users" ON "messages_users"."user_id" = "users"."id" INNER JOIN "messages" ON "messages"."id" = "messages_users"."message_id" WHERE "accounts"."blocked" = $1 AND "messages"."msg_status" = $2 AND "accounts"."email_notify" = $3 [["blocked", "f"], ["msg_status", "new"], ["email_notify", "t"]]
Message Load (0.5ms) SELECT "messages".* FROM "messages" WHERE "messages"."msg_status" = $1 [["msg_status", "new"]]
Completed 500 Internal Server Error in 3116ms (ActiveRecord: 38.0ms)
NoMethodError (undefined method `without_projects' for #<Message::ActiveRecord_Relation:0x0000000a805fc0>):
app/models/message.rb:24:in `block in sender'
app/models/message.rb:23:in `sender'
app/controllers/groups_controller.rb:47:in `index'
Rendered /.rvm/gems/ruby-2.0.0-p647/gems/actionpack-4.2.4/lib/action_dispatch/middleware/templates/rescues/_source.erb (19.6ms)
Rendered /.rvm/gems/ruby-2.0.0-p647/gems/actionpack-4.2.4/lib/action_dispatch/middleware/templates/rescues/_trace.html.erb (5.3ms)
Rendered /.rvm/gems/ruby-2.0.0-p647/gems/actionpack-4.2.4/lib/action_dispatch/middleware/templates/rescues/_request_and_response.html.erb (0.9ms)
Rendered /.rvm/gems/ruby-2.0.0-p647/gems/actionpack-4.2.4/lib/action_dispatch/middleware/templates/rescues/diagnostics.html.erb within rescues/layout (36.4ms)
Rendered /.rvm/gems/ruby-2.0.0-p647/gems/web-console-2.3.0/lib/web_console/templates/_markup.html.erb (0.7ms)
Rendered /.rvm/gems/ruby-2.0.0-p647/gems/web-console-2.3.0/lib/web_console/templates/_inner_console_markup.html.erb within layouts/inlined_string (0.5ms)
Rendered /.rvm/gems/ruby-2.0.0-p647/gems/web-console-2.3.0/lib/web_console/templates/_prompt_box_markup.html.erb within layouts/inlined_string (0.4ms)
Rendered /.rvm/gems/ruby-2.0.0-p647/gems/web-console-2.3.0/lib/web_console/templates/style.css.erb within layouts/inlined_string (0.3ms)
Rendered /.rvm/gems/ruby-2.0.0-p647/gems/web-console-2.3.0/lib/web_console/templates/console.js.erb within layouts/javascript (30.8ms)
Rendered /.rvm/gems/ruby-2.0.0-p647/gems/web-console-2.3.0/lib/web_console/templates/main.js.erb within layouts/javascript (0.4ms)
Rendered /.rvm/gems/ruby-2.0.0-p647/gems/web-console-2.3.0/lib/web_console/templates/error_page.js.erb within layouts/javascript (0.6ms)
Rendered /.rvm/gems/ruby-2.0.0-p647/gems/web-console-2.3.0/lib/web_console/templates/index.html.erb (78.9ms)