Person.exists?(1) # => true # SELECT 1 AS one FROM `job_offers` WHERE `job_offers`.`id` = 1 LIMIT 1 Person.exists?('id = 1') #=> false # SELECT 1 AS one FROM `job_offers` WHERE `job_offers`.`id` = 0 LIMIT 1 なぜか？ exists?にArrayもしくはH…