The number of users connected on the environment at the moment

The below query used to get the number of users connected on the environment at the moment.

   1:  select DISTINCT OPRID,

   2:                  LOGIPADDRESS,

   3:                  TO_CHAR(LOGINDTTM, 'YYYY-MM-DD:hh:mi:ss') LOGINTIME,

   4:                  TO_CHAR(LOGOUTDTTM, 'YYYY-MM-DD:hh:mi:ss') LOGOUTIME,

   5:                  TO_CHAR((sysdate), 'YYYY-MM-DD:hh:mi:ss') CURRTIME

   6:    FROM sysadm.PSACCESSLOG WHERE

   7:   (sysdate) - cast(LOGINDTTM as date)  >= 0

   8:   and cast(LOGOUTDTTM as date) - to_date(sysdate) >= 0

   9:   and LOGOUTDTTM = LOGINDTTM;

The information is still not accurate (If the user closes the browser or the connection crash).