rails3でarelを使ってSELECTでカラムを指定したいときはprojectではなくselect user_id_gt10 = User.where(User.arel_table[:id].gt(10)) columns = [User.arel_table[:id], User.arel_table[:name]] user_id_gt10.project(columns).to_sql => SELECT "users".*, "users"."id", "users"."name" FROM "users" WHERE ("users"."id" > 10) user_gt10.select(columns).to_sql => SELECT "users"."id", "users"."name" FROM "users" WHERE ("users"."id" > 10)