SqlServer判断表、列不存在则创建

一、表不存在则创建：

if not exists (select * from sysobjects where id = object_id(\'mytab\') 
and OBJECTPROPERTY(id, \'IsUserTable\') = 1)
create table  mytab
(
   id int,
   age int ,
   name varchar(max),
   primary key (id,age)
)
go

二、列不存在则创建。

if not exists (select * from syscolumns where id=object_id(\'mytab\') and name=\'columnname\') alter table [mytab] add columnname nvarchar(max)