Concern for PostgreSQL sort records by ID in one query

sortable.rb

module DokiCore
  module Concerns
    module Sortable
      extend ActiveSupport::Concern

      module ClassMethods

        # Run a "single" query to update multiple records by position.
        #
        # The Array of passed in IDs are sorted in the order they are
        # provided in the array.
        #
        # @param [Array] ids  IDs of records to sort
        #
        def sort_all_by(ids)
          ids = Array(ids)
          records = self.where({ id: ids })
          records.update_all([
            "position = (STRPOS(?, ','||lpad(cast(id as text), 20, '0')||',') - 1)/21 + 1",
            ",#{ids.map{|x| "%020d" % x }.join(',')},"
          ])
          records
        end

      end

    end
  end
end