Select data grouped by time over midnight - sql

Question

I have a table like:
ID TIMEVALUE
----- -------------
1 06.07.15 06:43:01,000000000
2 06.07.15 12:17:01,000000000
3 06.07.15 18:21:01,000000000
4 06.07.15 23:56:01,000000000
5 07.07.15 04:11:01,000000000
6 07.07.15 10:47:01,000000000
7 07.07.15 12:32:01,000000000
8 07.07.15 14:47:01,000000000
and I want to group this data by special times.
My current query looks like this:
SELECT TO_CHAR(TIMEVALUE, 'YYYY\MM\DD'), COUNT(ID),
SUM(CASE WHEN TO_CHAR(TIMEVALUE, 'HH24MI') <=700 THEN 1 ELSE 0 END) as morning,
SUM(CASE WHEN TO_CHAR(TIMEVALUE, 'HH24MI') >700 AND TO_CHAR(TIMEVALUE, 'HH24MI') <1400 THEN 1 ELSE 0 END) as daytime,
SUM(CASE WHEN TO_CHAR(TIMEVALUE, 'HH24MI') >=1400 THEN 1 ELSE 0 END) as evening FROM Table
WHERE TIMEVALUE >= to_timestamp('05.07.2015','DD.MM.YYYY')
GROUP BY TO_CHAR(TIMEVALUE, 'YYYY\MM\DD')
and I am getting this output
day overall morning daytime evening
----- ---------
2015\07\05 454 0 0 454
2015\07\06 599 113 250 236
2015\07\07 404 139 265 0
so that is fine grouping on the same day (0-7 o'clock, 7-14 o'clock and 14-24 o'clock)
But my question now is:
How can I group over midnight?
For example count from 6-14 , 14-23 and 23-6 o'clock on next day.
I hope you understand my question. You are welcome to even improve my upper query if there is a better solution.

Answer 1

EDIT: It is tested now: SQL Fiddle
The key is simply to adjust the group by so that anything before 6am gets grouped with the previous day. After that, the counts are pretty straight-forward.
SELECT TO_CHAR(CASE WHEN EXTRACT(HOUR FROM timevalue) < 6
THEN timevalue - 1
ELSE timevalue
END, 'YYYY\MM\DD') AS day,
COUNT(*) AS overall,
SUM(CASE WHEN EXTRACT(HOUR FROM timevalue) >= 6 AND EXTRACT(HOUR FROM timevalue) < 14
THEN 1 ELSE 0 END) AS morning,
SUM(CASE WHEN EXTRACT(HOUR FROM timevalue) >= 14 AND EXTRACT(HOUR FROM timevalue) < 23
THEN 1 ELSE 0 END) AS daytime,
SUM(CASE WHEN EXTRACT(HOUR FROM timevalue) < 6 OR EXTRACT(HOUR FROM timevalue) >= 23
THEN 1 ELSE 0 END) AS evening
FROM my_table
WHERE timevalue >= TO_TIMESTAMP('05.07.2015','DD.MM.YYYY')
GROUP BY TO_CHAR(CASE WHEN EXTRACT(HOUR FROM timevalue) < 6
THEN timevalue - 1
ELSE timevalue
END, 'YYYY\MM\DD');

Answer 2

Substract 1 day from timevalue for times lower than '06:00' at first and then:
SQLFiddle demo
select TO_CHAR(day, 'YYYY\MM\DD') day, COUNT(ID) cnt,
SUM(case when '23' < tvh or tvh <= '06' THEN 1 ELSE 0 END) as midnight,
SUM(case when '06' < tvh and tvh <= '14' THEN 1 ELSE 0 END) as daytime,
SUM(case when '14' < tvh and tvh <= '23' THEN 1 ELSE 0 END) as evening
FROM (
select id, to_char(TIMEVALUE, 'HH24') tvh,
trunc(case when (to_char(timevalue, 'hh24') <= '06')
then timevalue - interval '1' day
else timevalue end) day
from t1
)
GROUP BY day

Answer 3

Maybe you can do it like this (with some reformatting or PIVOT):
WITH spans AS
(SELECT TIMESTAMP '2015-01-01 00:00:00' + LEVEL * INTERVAL '1' HOUR AS start_time
FROM dual
CONNECT BY TIMESTAMP '2015-01-01 00:00:00' + LEVEL * INTERVAL '1' HOUR < LOCALTIMESTAMP),
t AS
(SELECT start_time, lead(start_time, 1) OVER (ORDER BY start_time) AS end_time, ROWNUM AS N
FROM spans
WHERE EXTRACT(HOUR FROM start_time) IN (6,14,23))
SELECT N, start_time, end_time, COUNT(*) AS ID_COUNT,
DECODE(EXTRACT(HOUR FROM start_time), 6,'morning', 14,'daytime', 23,'evening') AS daytime
FROM t
JOIN YOUR_TABLE WHERE TIMEVALUE BETWEEN start_time AND end_time
GROUP BY N;
Of course, the initial time value ('2015-01-01 00:00:00' in my example) has to be lower than the least date in your table.