View the number of Oracle connections and session conditions

Select B.machine, B.program, COUNT (*) from v$process A, v$session b where a.addr = B.paddr and b.username are NOT NULL GRO Up by B.machine, B.program ORDER by COUNT (*) desc

Or

View Session:
SELECT * FROM v$session where username are not null
Select Username,count (username) from v$session where username isn't null GROUP by username
Current number of connections:
Select COUNT (*) from v$process

View the number of Oracle connections and session conditions