数据库的基本操作之边删除边添加

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', drop age;Query OK, 0 rows affected (1.05 sec)Records: 0  Duplicates: 0  Warnings: 0查看执行上一步操作之后的结果<pre code_snippet_id="1943708" snippet_file_name="blog_20161022_1_4971184" name="code" class="sql">mysql> select * from users1;+----+----------+------+------+| id | username | pid  | sex  |+----+----------+------+------+|  3 | wuxie    |    2 | 3    ||  4 | Tom      |    1 | 3    |+----+----------+------+------+2 rows in set (0.00 sec)