MySQL 改变列的数据类型为ENUM

http://dev.mysql.com/doc/refman/5.6/en/alter-table-examples.html

作业要求建一个students的表:

create table Students
(  
    SID varchar(8),
    Name varchar(20),
    Category varchar(20)
);

后来发现category只有两个值，'undergraduate'和'graduate'.

alter table students modify category enum('undergraduate', 'graduate') not null default 'undergraduate';

MySQL 5.6