实例一：
select a.name columnname,c.name as typename,case when a.is_nullable =0 then 'Not Null' else 'Null' end as nullable,a.*
from sys.columns a , sys.objects b, sys.types c
where a.object_id= b.object_id and b.name='表名' and a.system_type_id=c.system_type_id order by a.column_id
实例二：
select
c.name as [字段名],t.name as [字段类型]
,convert(bit,c.IsNullable) as [可否为空]
,convert(bit,case when exists(select 1 from sysobjects where xtype='PK' and parent_obj=c.id and name in (
select name from sysindexes where indid in(
select indid from sysindexkeys where id = c.id and colid=c.colid))) then 1 else 0 end)
as [是否主键]
,convert(bit,COLUMNPROPERTY(c.id,c.name,'IsIdentity')) as [自动增长]
,c.Length as [占用字节]
,COLUMNPROPERTY(c.id,c.name,'PRECISION') as [长度]
,isnull(COLUMNPROPERTY(c.id,c.name,'Scale'),0) as [小数位数]
,ISNULL(CM.text,'') as [默认值]
,isnull(ETP.value,'') AS [字段描述]
--,ROW_NUMBER() OVER (ORDER BY C.name) AS [Row]
from syscolumns c
inner join systypes t on c.xusertype = t.xusertype
left join sys.extended_properties ETP on ETP.major_id = c.id and ETP.minor_id = c.colid and ETP.name ='MS_Description'
left join syscomments CM on c.cdefault=CM.id
where c.id = object_id('表名')
