This ruby script runs a SQL query and writes it as a CSV in the tmp folder using ruby's CSV library in a Ruby on Rails app

query_to_csv.rb

# run from console with `rails runner /path/to/this/file.rb`
# a timestamped file is placed in a Rails' app's tmp folder

require 'csv'

def file_path(name_of_file)
  Rails.root.join('tmp', "#{name_of_file}_#{sanitize_time(Time.zone.now)}.csv") # don't edit name set on line 22
end

def sanitize_time(time)
  time.to_s.gsub(/\s/, '_').gsub(/[\:\-]/, '')
end

def query
  "SELECT *
     FROM table
    WHERE thing;"
end

results = ActiveRecord::Base.connection.execute(query)

CSV.open(file_path('set_file_name_with_this_string'), 'w') do |csv|
  csv << ['column headers', 'as strings', 'in an array'] # replace strings with report's headers
  results.each do |result|
    csv << result
  end
end