DT
SELECT toStartOfMinute(event_datetime) datetime,
count()
FROM nginx.access_log
PREWHERE event_date BETWEEN toDate(toStartOfMinute(now()-3600)) AND toDate(toStartOfMinute(now())-1)
AND server_name = 'www.hello-world.ru'
WHERE event_datetime BETWEEN toStartOfMinute(now()-3600) AND toStartOfMinute(now())-1
GROUP BY datetime
ORDER BY datetime