菜鸟学堂：
select
(case when a.colorder=1 then d.name else '' end)表名,
a.colorder 字段序号,
a.name 字段名,
(case when columnproperty( a.id,a.name,'isidentity')=1 then '√'else '' end) 标识,
(case when (select count(*)
from sysobjects
where (name in
(select name
from sysindexes
where (id = a.id) and (indid in
(select indid
from sysindexkeys
where (id = a.id) and (colid in
(select colid
from syscolumns
where (id = a.id) and (name = a.name))))))) and
(xtype = 'pk'))>0 then '√' else '' end) 主键,
b.name 类型,
a.length 占用字节数,
columnproperty(a.id,a.name,'precision') as 长度,
isnull(columnproperty(a.id,a.name,'scale'),0) as 小数位数,
(case when a.isnullable=1 then '√'else '' end) 允许空,
isnull(e.text,'') 默认值,
isnull(g.[value],'') as 字段说明
from syscolumns a left join systypes b
on a.xtype=b.xusertype
inner join sysobjects d
on a.id=d.id and d.xtype='u' and d.name<>'dtproperties'
left join syscomments e
on a.cdefault=e.id
left join sysproperties g
on a.id=g.id and a.colid = g.smallid
order by a.id,a.colorder
