Ordered Funnel with Ahoy and ActiveRecord CTE

ahoy_cte.rb

event_1 = 'Landed on product page'
event_2 = 'Added product to card'
event_3 = 'Went to checkout'

ActiveRecord::Base.connection.exec_query(
  Ahoy::Event.with(
    event_1: Ahoy::Event.select(:visit_id, 'MIN(time) AS step_time')
                        .where(name: event_1)
                        .group(1),
    event_2: Ahoy::Event.select(:visit_id, 'MIN(time) AS step_time')
                        .joins('JOIN event_1 ON event_1.visit_id = ahoy_events.visit_id')
                        .where(name: event_2).where('ahoy_events.time >= event_1.step_time')
                        .group(1),
    event_3: Ahoy::Event.select(:visit_id, 'MIN(time) AS step_time')
                        .joins('JOIN event_2 ON event_2.visit_id = ahoy_events.visit_id')
                        .where(name: 'Attempted subscription').where('ahoy_events.time >= event_2.step_time')
                        .group(1),
    all_events: Arel::Nodes::Union.new(
      Arel::Table.new(:event_1).project("'#{event_1}' AS step_name", 'visit_id'),
      Arel::Nodes::Union.new(
        Arel::Table.new(:event_2).project("'#{event_2}' AS step_name", 'visit_id'),
        Arel::Table.new(:event_3).project("'#{event_3}' AS step_name", 'visit_id')
      )
    )
  )
  .select(:step_name, 'COUNT(visit_id)').from('all_events').group(1).to_sql
).to_ary

# [
#   {"step_name"=>"Landed on product page", "count"=>123},
#   {"step_name"=>"Added product to card", "count"=>84},
#   {"step_name"=>"Went to checkout", "count"=>43}
# ]