对于边删除边添加的情况，中间只需要用逗号隔开即可。

修改之前的数据表结构

mysql> select * from users1;
+----+----------+------+------+
| id | username | pid | sex |
+----+----------+------+------+
| 3 | wuxie | 2 | 3 |
| 4 | Tom | 1 | 3 |
+----+----------+------+------+
2 rows in set (0.00 sec)

执行边添加边删除

mysql> alter table users1 add sex enum(‘1‘, ‘2‘, ‘3‘) default ‘3‘;
Query OK, 0 rows affected (0.93 sec)
Records: 0 Duplicates: 0 Warnings: 0

查看执行上一步操作之后的结果

mysql> select * from users1;
+----+----------+------+------+
| id | username | pid | age |
+----+----------+------+------+
| 3 | wuxie | 2 | 10 |
| 4 | Tom | 1 | 10 |
+----+----------+------+------+
2 rows in set (0.00 sec)

数据库的基本操作之边删除边添加