http://blog.csdn.net/wuxiaokaixinguo/article/details/8293048 

检查数据库中是否存在某个表，不存在则生成该表

方法一：

IF NOT EXISTS (select * from dbo.sysobjects where xtype='U' and Name = 'T_Users')

BEGIN

  CREATE TABLE [dbo].[T_Users](userName varchar(20),userPass varchar(20));

END

方法二：

create procedure sel_tab

@table_name  varchar(20)

AS

  declare @flag int

  set @flag=0;

  set @flag = (select flag from (select count(*) as flag  from dbo.sysobjects where xtype='U' and Name = 'T_Users') as sel_count);

  if @flag = 0

  create table T_Users(userName varchar(20),userPass varchar(20));

GO

EXEC sel_tab "T_Users"

 

 

 判断列是否存在

if not exists(select * from syscolumns where id=object_id('TPARTNER') and name='AgencyPCC')

begin

   alter table dbo.TPARTNER  add AgencyPCC nvarchar(50) null

End

GO

 

select AgencyPCC,* from dbo.TPARTNER;

if exists(select * from syscolumns where id=object_id('TPARTNER') and name='AgencyPCC')

begin

   alter table dbo.TPARTNER drop COLUMN AgencyPCC

End

 

Create Table table1(ID Int)

GO

if  not exists (select Name From SysColumns Where ID = OBJECT_ID('table1') And Name = 'New_column')

ALTER TABLE  table1  ADD New_column VARCHAR(20)  NULL

GO

Select * From table1

GO

Drop Table table1

--Result

/*

ID New_column