select   count(*) 当前连接到SQLSERVER的用户数   
from   dbo.sysprocesses   
where   status   <> 'background '

------解决方案--------------------

SQL code
select   *
from   sys.sysprocesses   
WHERE nt_domain <>'本机名' AND nt_domain <>'' and net_address<>'' and  (nt_username <>'SYSTEM' OR net_library <>'LPC')
ORDER BY DBID DESC

------解决方案--------------------

查询连线的进程及其主机名,程序名.
SQL code

 select session_id,[host_name],[program_name]
 from sys.dm_exec_sessions
 where is_user_process=1