COL "HOUR FROM TO" FORM A20
PROMPT
PROMPT LOG SWITHCHES DONE ON
SET HEAD OFF
SELECT SYSDATE FROM DUAL
/
SET HEAD ON
select  to_char(to_date(time,'MM/DD/RR HH24:mi:ss'),' HH24')||':00'||' TO '||(to_char(to_date(time,'MM/DD/RR HH24:mi:ss'),' HH24') +1)||':00'  "HOUR FROM TO",
count(*) "LOG SWITCHES"
 from
v$log_history
WHERE
TO_CHAR(TO_DATE(TIME,'MM/DD/RR HH24:mi:ss'),'DD-MON-RR') = TO_CHAR(TO_DATE(SYSDATE),'DD-MON-RR')
group by to_char(to_date(time,'MM/DD/RR HH24:mi:ss'),' HH24')
order by "HOUR FROM TO"
/

PROMPT
PROMPT FREQUENCY OF LOG SWITCHES DONE OVERALL


select  to_char(to_date(time,'MM/DD/RR HH24:mi:ss'),'HH24')||':00'  HOUR,
count(*) from
v$log_history
group by to_char(to_date(time,'MM/DD/RR HH24:mi:ss'),'HH24')
order by HOUR
/