oracle sql query time periods union of set - sql

Question

i have a oracle database that has the following tables.How can i count the usage time of each room?
Time periods may overlap for each room,
The table structure is as follows。
t_room_electricity
+------------+--------------------+--------------------+
| roomcode | starttime | endtime |
+------------+--------------------+--------------------+
| 123 | 2019/5/10 10:00:00 | 2019/5/10 11:30:00 |
| 123 | 2019/5/10 10:30:00 | 2019/5/10 11:00:00 |
| 456 | 2019/5/10 11:00:00 | 2019/5/10 12:00:00 |
| 456 | 2019/5/10 13:00:00 | 2019/5/10 14:00:00 |
| 456 | 2019/5/10 13:30:00 | 2019/5/10 15:00:00 |
| 789 | 2019/6/10 14:22:00 | 2019/6/10 14:26:00 |
| 789 | 2019/6/10 14:31:00 | 2019/6/10 14:36:00 |
| 886 | 2019/6/10 14:32:00 | 2019/6/10 14:35:00 |
+------------+--------------------+--------------------+

Answer 1

Updating Answer to cater to the cases mentioned by OP.
USING MATCH_RECOGNIZE
with data
as (
select *
from t_room_electricity
match_recognize(
partition by roomcode
order by starttime
measures
first(starttime) f_starttime
,last(starttime) l_starttime
,first(endtime) f_endtime
,last(endtime) l_endtime
,min(starttime) as min_starttime
,max(endtime) as max_endtime
,match_number() as mn
,classifier() as cls
pattern(strt group1*)
define group1
as starttime<first(endtime)
)
)
select roomcode
,round(sum((max_endtime-min_starttime)*24*60)) as diff_in_minutes
from data
group by roomcode
See Output
https://dbfiddle.uk/?rdbms=oracle_18&fiddle=783140ede5dfbf8088a6ce77232ecef7
USING SQL
select x.roomcode
,count(distinct x.minutes_worked)
from (
select a.roomcode
,a.starttime
,a.endtime
,a.starttime + lvl/24/60 as minutes_worked
from t_room_electricity a
join (select level as lvl
from dual
connect by level<=24*60
)b
on b.lvl<=to_number((a.endtime-a.starttime)*24*60)
)x
group by x.roomcode
See output..
https://dbfiddle.uk/?rdbms=oracle_11.2&fiddle=2add9344f1335376b2fe32df21f769d6
Updated Answer to cater to overlaps, (based on a new recordset)
456 | 2019/5/10 11:00:00 | 2019/5/10 12:00:00 |
456 | 2019/5/10 13:00:00 | 2019/5/10 14:00:00 |
456 | 2019/5/10 13:30:00 | 2019/5/10 15:00:00 |
456 | 2019/5/10 13:45:00 | 2019/5/10 15:05:00 |
Considering overlaps the following query can achieve the intended result
select roomcode
,sum(round(time_in_minutes))
from (
select roomcode
,eventdate
,case when start_flag=1
and (lag(start_flag) over(partition by roomcode order by eventdate asc) = 0
or lag(start_flag) over(partition by roomcode order by eventdate asc) is null)
then null
else (eventdate
-
lag(eventdate) over(partition by roomcode order by eventdate asc)
)*24*60
end as time_in_minutes
from (
select roomcode,starttime as eventdate,1 as start_flag from t_room_electricity
union all
select roomcode,endtime as eventdate,0 as start_flag from t_room_electricity
)x
)y
group by roomcode
+----------+-----------------------------+
| ROOMCODE | SUM(ROUND(TIME_IN_MINUTES)) |
+----------+-----------------------------+
| 123 | 90 |
| 456 | 185 |
| 789 | 9 |
| 886 | 3 |
+----------+-----------------------------+
This first creates an inner block which stores each eventdatetime into a single column called EventDate.
Then the step is to check if the previous event was a closed boundary(ie start_flag=1) if it is then it begins counting, other wise it continues computing the difference between the previous event in minutes
After this the results are grouped by roomcode and the time_in_minutes is summed up
https://dbfiddle.uk/?rdbms=oracle_11.2&fiddle=650b4f0ad7304d7f44e7fabbca160a90
Old Answer
You can achieve this by using a group by expression as follows
select roomcode,sum((endtime-starttime)*24*60) as diff_in_minutes
from t_room_electricity
group by roomcode
+----------+-----------------+
| ROOMCODE | DIFF_IN_MINUTES |
+----------+-----------------+
| 123 | 120 |
| 789 | 9 |
| 456 | 210 |
| 886 | 3 |
+----------+-----------------+
See dbfiddle link.
https://dbfiddle.uk/?rdbms=oracle_11.2&fiddle=16fd05220157fd274cf0fab4e61c8802

Answer 2

Work with two tables like room:
with rooms AS
(SELECT 123 as room, to_date('2019/05/10 10:00:00', 'yyyy/mm/dd hh24:mi:ss') starttime, to_date('2019/05/10 11:30:00', 'yyyy/mm/dd hh24:mi:ss') endtime from dual
UNION ALL
SELECT 123 as room, to_date('2019/05/10 10:30:00', 'yyyy/mm/dd hh24:mi:ss') starttime, to_date('2019/05/10 11:00:00', 'yyyy/mm/dd hh24:mi:ss') endtime from dual
UNION ALL
SELECT 456 as room, to_date('2019/05/10 11:00:00', 'yyyy/mm/dd hh24:mi:ss') starttime, to_date('2019/05/10 12:00:00', 'yyyy/mm/dd hh24:mi:ss') endtime from dual
UNION ALL
SELECT 456 as room, to_date('2019/05/10 13:00:00', 'yyyy/mm/dd hh24:mi:ss') starttime, to_date('2019/05/10 14:00:00', 'yyyy/mm/dd hh24:mi:ss') endtime from dual
UNION ALL
SELECT 456 as room, to_date('2019/05/10 13:30:00', 'yyyy/mm/dd hh24:mi:ss') starttime, to_date('2019/05/10 15:00:00', 'yyyy/mm/dd hh24:mi:ss') endtime from dual
UNION ALL
SELECT 789 as room, to_date('2019/06/10 14:22:00', 'yyyy/mm/dd hh24:mi:ss') starttime, to_date('2019/06/10 14:26:00', 'yyyy/mm/dd hh24:mi:ss') endtime from dual
UNION ALL
SELECT 789 as room, to_date('2019/06/10 14:31:00', 'yyyy/mm/dd hh24:mi:ss') starttime, to_date('2019/06/10 14:36:00', 'yyyy/mm/dd hh24:mi:ss') endtime from dual
UNION ALL
SELECT 886 as room, to_date('2019/06/10 14:32:00', 'yyyy/mm/dd hh24:mi:ss') starttime, to_date('2019/06/10 14:35:00', 'yyyy/mm/dd hh24:mi:ss') endtime from dual)
select room, sum(round((endtime - starttime)*24*60)) from
(SELECT r1.room, min(r1.starttime) starttime, nvl(r2.endtime, r1.endtime) endtime
FROM rooms r1 left join
rooms r2
ON (r1.room = r2.room
AND r2.starttime between r1.starttime and r1.endtime
AND r2.starttime <> r1.starttime)
GROUP BY r1.room, nvl(r2.endtime, r1.endtime))
GROUP BY room
output:
789 9
123 60
456 180
886 3