Ruby on Rails - Dynamic SQL Query

Question

我正在我的一个控制器中执行以下原始sql查询：

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

有没有办法在此查询的最后一行添加一些 RoR 代码以动态生成code_id？

像这样：

AND subscriptions.code_id = '@subscription.code'

Answer 1

您可以在 heredoc 字符串中插入 Ruby 变量

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 = '#{@subscription.code}'  
SQL