mysql 有一些时间函数，虽然不常用，但是有时面试时会用到。

1.把当前时间转换成时间戳

select  UNIX_TIMESTAMP();

select name,birth,year(curdate())-year(birth())-(right(curdate(),5)-right(birth,5)) as age from peg oreder by name;

以上sql 输出的图像如下是：

+----------+------------+------------+------+

| name     | birth      | CURDATE()  | age  |

+----------+------------+------------+------+

| Bowser   | 1989-08-31 | 2003-08-19 |   13 |

| Buffy    | 1989-05-13 | 2003-08-19 |   14 |

| Chirpy   | 1998-09-11 | 2003-08-19 |    4 |

| Claws    | 1994-03-17 | 2003-08-19 |    9 |