修改列定义和表名

1.修改列定义
ALTER TABLE S MODIFY type TINYINT UNSIGNED NOT NULL;
ALTER TABLE S MODIFY type SMALLINT UNSIGNED NOT NULL FIRST
ALTER TABLE S ALTER TYPE SETdefault null;
alter table s alter type drop default;
修改列名
ALTER TABLE S CHANGE COLUMN create_tine c_time datetime;
修改表名
ALTER TABLE S RENAME student;

RENAME TABLE student TO S;