#查看表的结构
mysql> desc score; +------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +------------+--------------+------+-----+---------+----------------+ | id | int(4) | NO | PRI | NULL | auto_increment | | name | char(20) | NO | | NULL | | | score | double(16,2) | YES | | NULL | | | evaluation | char(20) | YES | | normal | | +------------+--------------+------+-----+---------+----------------+ 4 rows in set (0.00 sec)
#alter对字段操作
#添加字段
mysql> alter table exam_score add other int(4) default 10; Query OK, 0 rows affected (0.05 sec) Records: 0 Duplicates: 0 Warnings: 0
#修改字段变为另一个字段
mysql> alter table exam_score change other evaluation char(20) default ‘normal‘; Query OK, 4 rows affected (0.02 sec) Records: 4 Duplicates: 0 Warnings: 0
#删除字段(即删除字段中的所有数据)
mysql> alter table exam_score drop column other; Query OK, 0 rows affected (0.05 sec) Records: 0 Duplicates: 0 Warnings: 0
#修改表名
mysql> rename table exam_score to score; Query OK, 0 rows affected (0.01 sec)
时间: 2024-10-21 18:39:16