--(1)向数据库Student表中添加Name字段 use MR_NXT alter table student add Name nvarchar(20) --(2)将Student表中Name的字段的数据类型修改为varchar(50) use MR_NXT alter table student alter column Name varchar(50) --(3)删除Student表中Name字段 use MR_NXT alter table student drop column Name