--查询DB Time
  SELECT TO_CHAR(a.end_interval_time,'yyyymmdd hh24'),
      SUM (a.db_time) inst1_m,
      SUM (b.db_time) inst2_m
    FROM
      (SELECT pre_snap_id,
        snap_id,
        end_interval_time,
        ROUND((value - pre_value) / 1000000 / 60) db_time
      FROM
        (SELECT a.snap_id,
          end_interval_time,
          lag(a.snap_id) over(order by a.snap_id) pre_snap_id,
          value,
          lag(value) over(order by a.snap_id) pre_value
        FROM dba_hist_sys_time_model a,
          dba_hist_snapshot b
        WHERE stat_name      = 'DB time'
        AND a.dbid           = b.dbid
        AND a.snap_id        = b.snap_id
        AND a.instance_number=b.instance_number
        AND a.dbid           =
          (SELECT dbid FROM v$database
          )
        AND a.instance_number = 1
        )
      WHERE pre_snap_id   IS NOT NULL
    AND end_interval_time>sysdate-30
    ORDER BY snap_id DESC
    ) a,
    (SELECT pre_snap_id,
      snap_id,
      end_interval_time,
      ROUND((value - pre_value) / 1000000 / 60) db_time
    FROM
      (SELECT a.snap_id,
        end_interval_time,
        lag(a.snap_id) over(order by a.snap_id) pre_snap_id,
        value,
        lag(value) over(order by a.snap_id) pre_value
      FROM dba_hist_sys_time_model a,
        dba_hist_snapshot b
      WHERE stat_name      = 'DB time'
      AND a.dbid           = b.dbid
      AND a.snap_id        = b.snap_id
      AND a.instance_number=b.instance_number
      AND a.dbid           =
        (SELECT dbid FROM v$database
        )
      AND a.instance_number = 2
      )
    WHERE pre_snap_id   IS NOT NULL
    AND end_interval_time>sysdate-30
    ORDER BY snap_id DESC
    ) b
  WHERE a.snap_id=b.snap_id(+)
  GROUP BY TO_CHAR(a.end_interval_time,'yyyymmdd hh24')
  ORDER BY TO_CHAR(a.end_interval_time,'yyyymmdd hh24');