Oracle Database, What is an easy way to find all active db sessions (for all users) log in time (since when) using sql or em?

Oracle DBAs, What is an easy way to find all active db sessions (for all users) log in time (since 开发者_StackOverflow社区when)? I checked the sys view v$session and v$active_session_history, could not get that infor I want. I also checked on em client and em, seems no pages are showing it.

What, exactly, do you mean by "active"? If you mean Oracle's definition of active-- that the session is executing a SQL statement at this exact instant in time, I would think

SELECT username, status, logon_time
  FROM v$session
 WHERE status = 'ACTIVE'

If you have a different definition of "active" or if you are trying to determine the front-end user name in a three-tier application, can you explain your requirements a bit more?