先看看删除之前的表结构：

mysql> select * from test;
+------+--------+----------------------------------+------------+------------+------------+------------+
| t_id | t_name | t_password                       | t_birth    | birth      | birth1     | birth2     |
+------+--------+----------------------------------+------------+------------+------------+------------+
|    1 | name1  | 12345678901234567890123456789012 | NULL       | 1990-01-01 | 0000-00-00 | 2013-01-01 |
|    2 | name2  | 12345678901234567890123456789012 | 2013-01-01 | NULL       | 0000-00-00 | 2013-01-01 |
+------+--------+----------------------------------+------------+------------+------------+------------+
2 rows in set (0.00 sec)

执行删除命令，使用drop关键字。
基本的语法为：alter table <表名> drop column <字段名>;

具体的命令如下：

mysql> alter table test drop column birth1;
Query OK, 0 rows affected (0.13 sec)
Records: 0  Duplicates: 0  Warnings: 0

看看删除后的结果，是不是已经没有birth1字段了？

mysql> select * from test;
+------+--------+----------------------------------+------------+------------+------------+
| t_id | t_name | t_password                       | t_birth    | birth      | birth2     |
+------+--------+----------------------------------+------------+------------+------------+
|    1 | name1  | 12345678901234567890123456789012 | NULL       | 1990-01-01 | 2013-01-01 |
|    2 | name2  | 12345678901234567890123456789012 | 2013-01-01 | NULL       | 2013-01-01 |
+------+--------+----------------------------------+------------+------------+------------+
2 rows in set (0.00 sec)

关于MySQL中根据生日计算年龄的SQL语句日期函数，本文就介绍这么多，希望对大家有所帮助，谢谢！