Log every SQL query to database in Rails

Question

I want to save to a log file some SQL query rails performs, (namely the CREATE, UPDATE and DELETE ones) therefore I need to intercept all queries and then filter them maybe

Answer 1

Slightly updated version of @luca's answer for at least Rails 4 (and probably Rails 5)

Place this in config/initializers/sql_logger.rb:

connection = ActiveRecord::Base.connection
class << connection
  alias :original_exec :execute
  def execute(sql, *name)
    # try to log sql command but ignore any errors that occur in this block
    # we log before executing, in case the execution raises an error
    begin
      File.open(Rails.root.join("log/sql.log"), 'a') do |file|
        file.puts Time.now.to_s + ": " + sql
      end
    rescue Exception => e
      "Error logging SQL: #{e}"
    end
    # execute original statement
    original_exec(sql, *name)
  end
end