查询所有表以及记录数：select   a.name as 表名,max(b.rows) as 记录条数   from  sysobjects   a   ,sysindexes   b     where   a.id=b.id   and   a.xtype='u'   group   by   a.name   order by max(b.rows) desc

1.查询数据库中的所有数据库名：

 

SELECT Name FROM Master..SysDatabases ORDER BY Name

 

2.查询某个数据库中所有的表名：

SELECT Name FROM SysObjects Where XType='U' ORDER BY Name

 

3.查询表结构信息：

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_idleft join sys.extended_properties f on d.id=f.class and f.minor_id=0where b.name is not null--WHERE d.name='要查询的表' --如果只查询指定表,加上此条件order by a.id,a.colorder