logons current

This example was tested on an Oracle 9 database. The logons current statistic in V$SYSSTAT shows how many sessions are currently logged on:
  

SQL> SELECT VALUE FROM V$SYSSTAT WHERE NAME = 'logons current'
  2  /

     VALUE
---------- 
       205 

SQL> SELECT COUNT(*) FROM V$SESSION
  2  /

  COUNT(*)
---------- 
       205

SQL>