MySQL中的alter table操作之add/modify/drop列

alter table的操作有增加列、删除列和修改列的长度等

create table t1 (c1 int primary key) engine = innodb;// 增加一个列c2alter table t1 add c2 varchar(16379);drop table t1;create table t1 (c1 int primary key, c2 varchar(50)) engine = innodb;// 将列c2长度更改alter table t1 modify column c2 varchar(16234);drop table t1;// 删除一个列c2create table t1 (c1 int primary key, c2 varchar(50)) engine = innodb;alter table t1 drop column c2;drop table t1;