dbtimevalue

 select snap_id ,value/(1000000) dbtimevalue
from (
select snap_id,STAT_NAME, value - lag( value) over ( partition by stat_name order by snap_id ) value
from dba_hist_sys_time_model
where snap_id between &&begin_snap_id and &&end_snap_id and instance_number = userenv('INSTANCE') order by snap_Id )
where stat_name like 'DB t%'
--and value > 0
and snap_id != &&begin_snap_id