set lines 100 pages 999
col ID format a15
select username
,      sid || ',' || serial# "ID"
,      status
,      last_call_et "Last Activity"
from   v$session
where  username is not null
order by status desc
,        last_call_et desc

May be the above query correct for exhibiting Session ID, Owner╩╝s username and also the session status (whether it's Waiting or On CPU) ? kindly advise