快照会话数查询

SELECT A.SNAP_ID,
TO_CHAR(B.END_INTERVAL_TIME, 'mm-dd_hh24:mi') SNAP_TIME,
SUM(DECODE(A.STAT_NAME, 'logons current', A.VALUE, 0)) LOGON_CURRENT
FROM DBA_HIST_SYSSTAT A, DBA_HIST_SNAPSHOT B
WHERE A.DBID = B.DBID
AND A.INSTANCE_NUMBER = B.INSTANCE_NUMBER
AND A.SNAP_ID = B.SNAP_ID
AND B.END_INTERVAL_TIME >= TRUNC(SYSDATE - 7)
AND B.END_INTERVAL_TIME <= TRUNC(SYSDATE)
AND A.STAT_NAME = 'logons current'
GROUP BY A.SNAP_ID, B.END_INTERVAL_TIME
ORDER BY 1