mysql> select abs(3-5); +----------+ | abs(3-5) | +----------+ | 2 | +----------+ 1 row in set (0.00 sec) 相关文章: 2021-12-19 2021-11-21 2022-01-26 2022-12-23 2022-12-23 2022-02-17 2021-10-19 2022-12-23