--查询数据库中的所有数据库名：

 SELECT * FROM Master..SysDatabases ORDER BY Name

 --查询某个数据库中所有的表名：

 select * from sysobjects where type='U'

 --查询表结构

 SELECT (case when a.colorder=1 then d.name else null 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 [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 sys.extended_properties g on a.id=g.major_id AND a.colid=g.minor_id

 left join sys.extended_properties f on d.id=f.class and f.minor_id=0

 where

 -- b.name is not null

  d.name='File_Folder_Name' --如果只查询指定表,加上此条件

 order by a.id,a.colorder