РЕДАКТИРАНЕ :Тествано е сега:SQL Fiddle
Ключът е просто да коригирате group by
така че всичко преди 6 сутринта да се групира с предишния ден. След това преброяването е доста лесно.
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');