comparison of Symbol with 100 failed - ruby-on-rails

Question

I am re-writing a program called Emissions Gateway to the new version of Ruby on Rails.
I have a method that was written with syntax from a gem called Squeel and I am having a very hard time re-writing it. I have been failing at it for over 4 hours and can't seem to get it figured out.
This is the method right here, it is in a model called datalogger.rb along with the schema information for the datalogger.rb model.
# == Schema Information
#
# Table name: dataloggers
#
# id :integer not null, primary key
# project_id :integer
# created_at :datetime not null
# updated_at :datetime not null
# original_file_name :string(255)
# original_content_type :string(255)
# original_file_size :integer
# original_updated_at :datetime
# status :string(255) default("incomplete")
# hours :integer
# readings_total :integer
# readings_start :datetime
# readings_stop :datetime
# direct_upload_url :string(255)
# version :string(255)
# comments :string(255)
# bypass :boolean default(FALSE)
# device_id :integer
# device_name :string(255)
# device_description :string(255)
# device_serial :integer
# md5 :string(255)
# user_id :integer
# reported_at :datetime
# user_reported_id :integer
# reported :boolean
def stats(temperatures)
unless bypass
#temperatures = temperatures
#stats = {}
#cumulative_percent_at = 0
#cumulative_readings = 0
#temperatures.each_cons(2) do |current_n, next_n|
# puts "Evaluating #{current_n} and #{next_n}"
#stats["#{next_n}"] = {}
# CHANGED v0.009 9/27/2021 Scott Milella
# readings_at = readings.where{(temperature.gt current_n) & (temperature.lteq next_n)}.sum(:frequency)
readings_at = Reading.where(:temperature > current_n).and(:temperature <= next_n).sum(:frequency)
#stats["#{next_n}"][:readings] = readings_at
# puts "Readings at: #{readings_at}"
# #cumulative_readings = #stats.map{|_, v| v[:readings] }.sum
# puts "Cumulative Readings: #{cumulative_readings}"
percent_at = ((readings_at.to_f / readings_total) * 100 )
#stats["#{next_n}"][:time_at] = percent_at
#cumulative_percent_at += percent_at
# puts "Percent at: #{percent_at}%"
# puts "Cumulative Percent at: #{#cumulative_percent_at}"
percent_over = 100 - #cumulative_percent_at
#stats["#{next_n}"][:over] = percent_over
# puts "Percent Over: #{percent_over}%"
# puts "Progress: #{#cumulative_readings}/#{readings_total} readings"
end
end
This is the method I changed:
readings_at = Reading.where(:temperature > current_n)
.and(:temperature <= next_n).sum(:frequency)
You can see what I changed above in the method as well as I indicate it with # CHANGED. It is giving me this error called comparison of Symbol with 100 failed which makes NO Sense to me because the :symbol is an integer from another model called Reading.
Here is that model:
# == Schema Information
#
# Table name: readings
#
# id :integer not null, primary key
# temperature :integer
# frequency :integer
# datalogger_id :integer
#
class Reading < ActiveRecord::Base
belongs_to :datalogger
attr_accessible :frequency, :temperature, :datalogger_id
validates_presence_of :frequency, :temperature, :datalogger_id
end
I don't understand why I can't compare an Integer with an Integer regardless if it is in a symbol or not? Do I have the Syntax wrong or something? It isn't giving me a syntax error. I have tried about 1000 other ways to write it and I get a variety of errors from > not found in Array to all kinds of other things. If anyone wants to see the whole datalogger.rb model I will post it, it's rather long and it seems to be just this method that the problem exists in.
Here is a single line I have captured from the SQL out of the current version of Emissions Gateway that is working: You can see the number 272 should be current_n and the 150 is the next_n I can verify those values on the better_errors console. So I don't understand where I am going wrong. I am guessing it might have something to do with the each_cons method perhaps which I do not understand.
I modified it so you could see the SQL all in one place, otherwise it was displaying as one long line. I will show it after just in case it is confusing:
2021-09-27T18:50:49.173173+00:00 app[web.1]: (1.5ms) SELECT SUM("readings"."frequency")
AS sum_id FROM "readings"
WHERE "readings"."datalogger_id" = 272
AND (("readings"."temperature" > 100
AND "readings"."temperature" <= 150))
The SQL as it comes out
2021-09-27T18:50:49.173173+00:00 app[web.1]: (1.5ms) SELECT SUM("readings"."frequency") AS sum_id FROM "readings" WHERE "readings"."datalogger_id" = 272 AND (("readings"."temperature" > 100 AND "readings"."temperature" <= 150))
If anyone can point out how I need to re-write this method I would be greatly appreciative, I have tried for hours and am getting noplace.
Here is the instructions for squeel in case anyone needs to see the instructions.
https://github.com/activerecord-hackery/squeel
I wish that gem had NEVER been written, has caused me so much pain it is unreal!
Thank You,
Scott

Answer 1

Ok, let's take a deep look into your query:
readings_at = Reading.where(:temperature > current_n).and(:temperature <= next_n).sum(:frequency)
Both :temperature > current_n and :temperature <= next_m are comparing symbols (left side) with integers (right side). That's why you are getting an ArgumentError.
The Rails syntax to achieve what you are doing is:
readings_at = Reading.where('temperature > ? AND temperature <= ?', current_n, next_n).sum(:frequency)
Or, if you prefer, adding multiples where will add an AND clause to your query. So the below is equivalent:
readings_at = Reading.where('temperature > ?', current_n).where('temperature <= ?', next_n).sum(:frequency)
Using the ? guarantee that Rails is going to "clean" this input for you in order to prevent SQL injection.