增加列:

alter table table_name add name varchar(100);

alter table table_name add name varchar(100) after id;

alter table table_name add name varchar(100) first;

修改列名:

alter table table_name change name name varchar(10);

#change可改名字与字段类型

mysql> alter table a change uid uid int;

Query OK, 0 rows affected (0.04 sec)

Records: 0  Duplicates: 0  Warnings: 0

alter table table_name modify name int;

#modify只改字段类型

mysql> desc a;

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

| Field | Type    | Null | Key | Default | Extra |

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

| namea | char(1) | YES  |     | NULL    |       |

| id    | int(11) | YES  |     | NULL    |       |

| uid   | int(11) | YES  |     | NULL    |       |

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

3 rows in set (0.01 sec)

mysql>

mysql>

mysql> alter table a modify uid varchar(1);

Query OK, 0 rows affected (0.07 sec)

Records: 0  Duplicates: 0  Warnings: 0

mysql> desc a;

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

| Field | Type       | Null | Key | Default | Extra |

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

| namea | char(1)    | YES  |     | NULL    |       |

| id    | int(11)    | YES  |     | NULL    |       |

| uid   | varchar(1) | YES  |     | NULL    |       |

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

3 rows in set (0.01 sec)

mysql>

删除列:

alter table table_name drop column_name;

#手册

help modify;