Oracle Session Tips

SQL> select  b.MACHINE, b.PROGRAM , count(*) from v$process a, v$session b where a.ADDR = b.PADDR and  b.USERNAME is not null   group by  b.MACHINE  , b.PROGRAM order by count(*) desc;

MACHINE                                                                                                          PROGRAM                                                                                     COUNT(*)
-------------------------------------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------ ----------
iZwz92mfhsio3n38nswnocZ                                                                                          JDBC Thin Client                                                                                           1
izwz9fw6w9bctb8caet90bz                                                                                          sqlplus@izwz9fw6w9bctb8caet90bz (TNS V1-V3)                                                                1

SQL> 
SQL> select username,count(username) from v$session where username is not null group by username
  2  ;

USERNAME                                                     COUNT(USERNAME)
------------------------------------------------------------ ---------------
APPS                                                                       1
SYS                                                                        1

SQL> 

Session:
select * from v$session where username is not null;

Process:
select count(*) from v$process;