SQL Server中增加列、修改列的字段类型、删除列

 

 

alter table table_name add column_name column_tpye ----增加列
-----例：alter table Students add Email varchar(16)

alter table table_name alter column column_name column_type ---修改列
-----例：alter table Students alter column Email varchar(255)

alter table table_name drop column column_name ---删除列
------例：alter table Students drop column Email