select       [表名]=c.Name,     [表说明]=isnull(f.[value],''),      [列名]=a.Name,      [列序号]=a.Column_id,      [标识]=case when is_identity=1 then '是' else '' end,      [主键]=case when exists(select 1 from sys.objects x join sys.indexes y on x.Type=N'PK' and x.Name=y.Name                           join sysindexkeys z on z.ID=a.Object_id and z.indid=y.index_id and z.Colid=a.Column_id)                      then '是' else '' end,      [类型]=b.Name,      [字节数]=case when a.[max_length]=-1 and b.Name!='xml' then 'max/2G'               when b.Name='xml' then '2^31-1字节/2G'              else rtrim(a.[max_length]) end,      [长度]=case when ColumnProperty(a.object_id,a.Name,'Precision')=-1 then '2^31-1'                  else rtrim(ColumnProperty(a.object_id,a.Name,'Precision')) end,      [小数]=isnull(ColumnProperty(a.object_id,a.Name,'Scale'),0),      [是否为空]=case when a.is_nullable=1 then '是' else '' end,      [列说明]=isnull(e.[value],''),      [默认值]=isnull(d.text,'')      from       sys.columns a  left join      sys.types b on a.user_type_id=b.user_type_id  inner join      sys.objects c on a.object_id=c.object_id and c.Type='U'  left join      syscomments d on a.default_object_id=d.ID  left join      sys.extended_properties e on e.major_id=c.object_id and e.minor_id=a.Column_id and e.class=1   left join      sys.extended_properties f on f.major_id=c.object_id and f.minor_id=0 and f.class=1