sql创建表格 转载

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