Group records by time

Question

I have a table containing a datetime column and some misc other columns. The datetime column represents an event happening. It can either contains a time (event happened at

Answer 1

Give this a try:

select datetime((strftime('%s', time) / 900) * 900, 'unixepoch') interval,
       count(*) cnt
from t
group by interval
order by interval

Check the fiddle here.