Database Uptime

Database Uptime (11g):

col d_name heading 'Database' format a8
col v_logon_time heading 'Startup'
col dh_uptime heading 'Uptime' format a30

select upper(sys_context('USERENV','DB_NAME')) d_name,
       to_char(logon_time,'DD-MON-YYYY hh24:mi:ss') v_logon_time,
       to_char(trunc(sysdate-logon_time,0))||' days, '||trunc(((sysdate-logon_time)-floor(sysdate-logon_time))*24)||' Hours' dh_uptime
  from sys.v_$session
 where sid=1 /* pmon session */
/

Sample Output:

Database Startup              Uptime
-------- -------------------- ------------------------------
MYDB     05-JUL-2012 21:42:24 32 days, 13 Hours