create proc addcolumn
@tablename varchar(30),--表名
@colname varchar(30),--要加的列名
@coltype varchar(100),--要加的列类型
@colid int --加到第几列
asdeclare @colid_max int
declare @sql varchar(1000) --动态sql语句
--------------------------------------------------
if not exists(select 1 from sysobjects
where name = @tablename and xtype = 'u')
begin
raiserror 20001 '没有这个表'
return -1
end
--------------------------------------------------
if exists(select 1 from syscolumns
where id = object_id(@tablename) and name = @colname)
begin
raiserror 20002 '这个表已经有这个列了！'
return -1
end
--------------------------------------------------

--保证该表的colid是连续的

select @colid_max = max(colid) from syscolumns where id=object_id(@tablename)if @colid > @colid_max or @colid < 1
set @colid = @colid + 1
--------------------------------------------------
set @sql = 'alter table '+@tablename+' add '+@colname+' '+@coltype
exec(@sql)select @colid_max = colid
from syscolumns where id = object_id(@tablename) and name = @colname
if @@rowcount <> 1
begin
raiserror 20003 '加一个新列不成功，请检查你的列类型是否正确'
return -1
end
--------------------------------------------------

--打开修改系统表的开关

EXEC sp_configure 'allow updates',1 RECONFIGURE WITH OVERRIDE

--将新列列号暂置为-1

set @sql = 'update syscolumns
set colid = -1
where id = object_id('''+@tablename+''')
and colid = '+cast(@colid_max as varchar(10))
exec(@sql)

--将其他列的列号加1

set @sql = 'update syscolumns
set colid = colid + 1
where id = object_id('''+@tablename+''')
and colid >= '+cast(@colid as varchar(10))
exec(@sql)

--将新列列号复位

set @sql = 'update syscolumns
set colid = '+cast(@colid as varchar(10))+'
where id = object_id('''+@tablename+''')
and name = '''+@colname +''''
exec(@sql)
--------------------------------------------------

--关闭修改系统表的开关

EXEC sp_configure 'allow updates',0 RECONFIGURE WITH OVERRIDE
go

<FONT style="COLOR: #ff0000">调用方法：

exec addcolumn '表名','新列名','新列类型',加到第几个位置

<FONT style="COLOR: #ff0000">如：

exec addcolumn 'test','id2','char(10)',2
表示将id2这个列加到表test的第二个位置，类型是char(10)。