Extract DB Time from Awr

Here’s a handy little script for showing when the database has been most busy. 
thanks to kerry http://kerryosborne.oracle-guy.com

select * from (

select begin_snap, end_snap, timestamp begin_timestamp, inst, a/1000000/60 DBtime from

(

select

 e.snap_id end_snap,

 lag(e.snap_id) over (order by e.snap_id) begin_snap,

 lag(s.end_interval_time) over (order by e.snap_id) timestamp,

 s.instance_number inst,

 e.value,

 nvl(value-lag(value) over (order by e.snap_id),0) a

from dba_hist_sys_time_model e, DBA_HIST_SNAPSHOT s

where s.snap_id = e.snap_id

 and e.instance_number = s.instance_number

 and to_char(e.instance_number) like nvl('&instance_number',to_char(e.instance_number))

 and stat_name             = 'DB time'

)

where  begin_snap between nvl('&begin_snap_id',0) and nvl('&end_snap_id',99999999)

and begin_snap=end_snap-1

order by dbtime desc

)

where rownum < 31