1class MigrateExerciseIdToExerciseSets < ActiveRecord::Migration
 2  def change
 3    ExerciseSet.where(exercise_id: nil).find_each do |set|
 4      result = execute(
 5      <<-SQL
 6SELECT ew.exercise_id
 7FROM exercise_sessions es
 8INNER JOIN exercise_workouts ew on ew.id = es.exercise_workout_id
 9WHERE es.id = '#{set.exercise_session_id}'
10      SQL
11      )
12      exercise_id = result.first["exercise_id"]
13      say "updating set: #{set.id} to exercise: #{exercise_id}"
14      set.update_column(:exercise_id, exercise_id)
15    end
16  end
17end