How to make raw SQL query chainable using Scope? -Rails - sql

Question

I have written a SQL and i want this to be chainable or i can use this query as a scope in Rails? any thoughts?
select '{Critical: '||"Critical"||', Major: '||"Major"||', Moderate:
'||"Moderate"||', Minor: '||"Minor"||', Clear: '||"Clear"||'}' as result
from (
select
sum(case when max_weight=1 THEN 1 else 0 End ) as "Clear",
sum(case when max_weight=2 THEN 1 else 0 End ) as "Minor",
sum(case when max_weight=3 THEN 1 else 0 End ) as "Moderate",
sum(case when max_weight=22 THEN 1 else 0 End ) as "Major",
sum(case when max_weight=160 THEN 1 else 0 End ) as "Critical",
count(*) as number_of_answers
from (
select
fua.forms_user_id,
max(fa.weight) max_weight
from
public.forms_user_answers fua
join public.forms_users fu on (fua.forms_user_id = fu.id)
left join public.form_answers fa on (fua.form_answer_id = fa.id)
where
fu.form_id = #{form.id}
group by
fua.forms_user_id
) subq
) subq1

Answer 1

It's unlikely you'll be able to make that kind of query chainable with ActiveRecord. But you can certainly make a scope for the query in Rails:
scope :my_scope, -> {
self.connection.execute("
select '{Critical: '||"Critical"||', Major: '||"Major"||', Moderate:
'||"Moderate"||', Minor: '||"Minor"||', Clear: '||"Clear"||'}' as result
from (
select
sum(case when max_weight=1 THEN 1 else 0 End ) as "Clear",
sum(case when max_weight=2 THEN 1 else 0 End ) as "Minor",
sum(case when max_weight=3 THEN 1 else 0 End ) as "Moderate",
sum(case when max_weight=22 THEN 1 else 0 End ) as "Major",
sum(case when max_weight=160 THEN 1 else 0 End ) as "Critical",
count(*) as number_of_answers
from (
select
fua.forms_user_id,
max(fa.weight) max_weight
from
public.forms_user_answers fua
join public.forms_users fu on (fua.forms_user_id = fu.id)
left join public.form_answers fa on (fua.form_answer_id = fa.id)
where
fu.form_id = #{form.id}
group by
fua.forms_user_id
) subq
) subq1
")
}