where select max(age) from class是为了找最大的age from (select * from class where id < 4) as tep后面的as tep是给临时表起一个名 exists 相关文章: 2021-08-09 2022-12-23 2022-01-17 2022-12-23 2021-08-09 2021-10-16 2022-12-23