Chaining multiple ActiveRecord `or` queries - ruby-on-rails

Question

I've got an array of columns that I want to loop through and optionally chain an or query onto an ActiveRecord query chain. I can get it to work, but the resulting query appends the or onto the query chain, therefore making the columns in my inital query optional. Here's my class:
class Claim
class MatchingAttributeFinder
ATTRIBUTE_GROUPS_TO_MATCH = [
["teacher_reference_number"],
["email_address"],
["national_insurance_number"],
["bank_account_number", "bank_sort_code", "building_society_roll_number"],
].freeze
def initialize(source_claim, claims_to_compare = Claim.submitted)
#source_claim = source_claim
#claims_to_compare = claims_to_compare
end
def matching_claims
claims = #claims_to_compare.where.not(id: #source_claim.id)
ATTRIBUTE_GROUPS_TO_MATCH.each do |attributes|
vals = values_for_attributes(attributes)
next if vals.blank?
concatenated_columns = "CONCAT(#{attributes.join(",")})"
claims = claims.or(
Claim.where("LOWER(#{concatenated_columns}) = LOWER(?)", vals.join)
)
end
claims
end
private
def values_for_attributes(attributes)
attributes.map { |attribute|
#source_claim.read_attribute(attribute)
}.reject(&:blank?)
end
end
end
The generated SQL looks like this:
SELECT "claims".* FROM "claims" WHERE (((("claims"."submitted_at" IS NOT NULL AND "claims"."id" != 'a7b25b99-4477-42b1-96ab-8262582c5541' OR (LOWER(CONCAT(teacher_reference_number)) = LOWER('0902344'))) OR (LOWER(CONCAT(email_address)) = LOWER('genghis.khan#mongol-empire.com'))) OR (LOWER(CONCAT(national_insurance_number)) = LOWER('QQ891011C'))) OR (LOWER(CONCAT(bank_account_number,bank_sort_code,building_society_roll_number)) = LOWER('34682151972654123456789/ABCD')))
But what I actually want is more like this:
SELECT "claims".* FROM "claims" WHERE "claims"."submitted_at" IS NOT NULL AND "claims"."id" != 'd6a53b4d-c569-49e6-a2ea-ac44b69b0451' AND (LOWER(concat(teacher_reference_number)) = LOWER('0902344') OR LOWER(concat(email_address)) = LOWER('genghis.khan#mongol-empire.com') OR LOWER(concat(national_insurance_number)) = LOWER('QQ891011C') OR LOWER(concat(bank_account_number,bank_sort_code,building_society_roll_number)) = LOWER('34682151972654123456789/ABCD'))
Is there any way to set up something like an empty scope that I can chain my OR queries to?

Answer 1

Try chaning all the "or" together first and then chain the original query
def matching_claims
claims = #claims_to_compare.where.not(id: #source_claim.id)
ors = nil
ATTRIBUTE_GROUPS_TO_MATCH.each do |attributes|
vals = values_for_attributes(attributes)
next if vals.blank?
concatenated_columns = "CONCAT(#{attributes.join(",")})"
aux = Claim.where("LOWER(#{concatenated_columns}) = LOWER(?)", vals.join)
if ors.nil?
ors = aux
else
ors = ors.or(aux)
end
end
claims.merge(ors)
end