Current session wait activity in DB

Create Or Replace Force View Sys.Av_db_cur_sess_wait_activity (Sid,
                                                               Username,
                                                               Wait_class,
                                                               Total_waits,
                                                               Time_waited_secs,
                                                               Killstmt
                                                              )
As
   Select   A.Sid, B.Username, A.Wait_class, A.Total_waits,
            Round ((A.Time_waited / 100), 2) Time_waited_secs,
               'Alter SYSTEM Kill Session '
            || ''''
            || B.Sid
            || ','
            || B.Serial#
            || ''' '
            || 'IMMEDIATE;' Killstmt
       From Sys.V_$session_wait_class A, Sys.V_$session B
      Where B.Sid = A.Sid
        And B.Username Is Not Null
        And A.Wait_class != 'Idle'
   Order By 5 Desc;