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;
时间: 2024-10-09 11:02:31