Group by hour

Question

Hello,
I have at table with a date field (dd/mm/yyyy hh)
How do I group by hh ?
I want something like the below:
SELECT TRUNC(DATE_FIELD) COUNT(*)
FROM MYTABLE
GROUP BY TRUNC(DATE_FIELD);
but this will group by dd/mm/yy
I need the same query but group by dd/mm/yyyy hh
Thank you in advance.

Answer 1

Hi,
drbiloukos wrote:
Hello,
I have at table with a date field (dd/mm/yyyy hh)
How do I group by hh ?
I want something like the below:
SELECT TRUNC(DATE_FIELD) COUNT(*)
FROM MYTABLE
GROUP BY TRUNC(DATE_FIELD);
but this will group by dd/mm/yy
I need the same query but group by dd/mm/yyyy hh
Thank you in advance.TRUNC (d) with only 1 argument is the same as
TRUNC (d, 'DD'): it maps all DATEs in the same calendar day to the first DATE in that day.
TRUNC (d, 'HH') maps all DATEs in the same hour to the first DATE in that hour.
SELECT    TRUNC (DATE_FIELD, 'HH')    AS hr
,         COUNT (*)                     AS cnt
FROM      MYTABLE
GROUP BY  TRUNC (DATE_FIELD, 'HH')
;