mysql 修改表列

create table behavior(userid varchar(40) not null,date varchar(15) not nu
ll,T int(10),P varchar(20),I varchar(10),U varchar(5000),A varchar(10),B varchar
(10),V varchar(100),W varchar(10),N varchar(20),C varchar(20));

ALTER TABLE behavior  MODIFY COLUMN P  VARCHAR(14)  CHARACTER SET gbk COLLATE gbk_chinese_ci NOT NULL;

ALTER TABLE behavior   MODIFY COLUMN P  VARCHAR(14)