User.order('rand()').first
User Load (2.5ms) SELECT `users`.* FROM `users` ORDER BY rand() LIMIT 1
User.select(:id).order('rand()').first.reload
User Load (0.3ms) SELECT id FROM `users` ORDER BY rand() LIMIT 1
User Load (0.1ms) SELECT `users`.* FROM `users` WHERE `users`.`id` = 20 LIMIT 1