查最近7天的DB Time

WITH sysstat AS
(select sn.begin_interval_time begin_interval_time,
sn.end_interval_time end_interval_time,
ss.stat_name stat_name,
ss.value e_value,
lag(ss.value, 1) over(order by ss.snap_id) b_value
from dba_hist_sysstat ss, dba_hist_snapshot sn
where trunc(sn.begin_interval_time) >= sysdate - 7
and ss.snap_id = sn.snap_id
and ss.dbid = sn.dbid
and ss.instance_number = sn.instance_number
and ss.dbid = (select dbid from v$database)
and ss.instance_number = (select instance_number from v$instance)
and ss.stat_name = 'DB time')
select to_char (BEGIN_INTERVAL_TIME, 'mm-dd hh24:mi') || to_char (END_INTERVAL_TIME, '
hh24:mi') date_time, stat_name, round((e_value - nvl(b_value, 0)) / (extract(day
from(end_interval_time - begin_interval_time)) * 24 * 60 * 60 + extract(hour
from(end_interval_time - begin_interval_time)) * 60 * 60 + extract(minute
from(end_interval_time - begin_interval_time)) * 60 + extract(second
from(end_interval_time - begin_interval_time))), 0) per_sec
from sysstat
where(e_value - nvl(b_value, 0)) > 0 and nvl(b_value, 0) > 0
/