统计RAC历史快照中 session 个数

select
   snap.instance_number,to_char(snap.begin_interval_time,'yyyy-mm-dd HH24:MM:ss'), session_count.value session_count
from
    DBA_HIST_SYSSTAT session_count,
    DBA_HIST_SNAPSHOT snap
where
    session_count.stat_id = (select stat_id from v$statname where name ='logons current' )
    and snap.snap_id =session_count.snap_id
    and snap.instance_number =session_count.instance_number
    and session_count.dbid= snap.dbid
    
    order by  begin_interval_time