active_users_query = <<-sql 
       SELECT count(DISTINCT patients.id)
       FROM public.patients,public.subscriptions,public.users,public.calendar_days
       WHERE patients.user_id = users.id 
       AND patients.id = calendar_days.patient_id 
       AND subscriptions.user_id = patients.user_id 
       AND (date_trunc('day',patients.last_sync) > current_date - interval '30 days' 
       OR date_trunc('day',calendar_days.created_at) > current_date - interval '30 days' 
       OR date_trunc('day',users.current_sign_in_at) > current_date - interval '30 days') 
       AND subscriptions.code_id = 2  
sql

有没有办法可以在这个查询的最后一行添加一些RoR代码来动态生成code_id？

像这样的东西：

AND subscriptions.code_id = '@subscription.code'