How to Get the Current Date and Time in ClickHouse

now() returns a DateTime with second precision; use now64() when you need milliseconds. today() and yesterday() return Date values, which are cheaper to compare against a Date-typed partition key. The toStartOf family (toStartOfDay, toStartOfHour, toStartOfMonth) is how you bucket timestamps for time-series grouping.

SELECT now(), today(), yesterday(), toStartOfDay(now());

Timezones

ClickHouse stores DateTime as a UTC instant and applies a timezone only when rendering it. Passing a timezone name changes the zone used for that conversion, so toDate(now(), 'America/New_York') can return a different day than toDate(now()). Set the session default with SET timezone = 'Europe/Helsinki' if every query needs the same zone.

SELECT now('Europe/Helsinki'), toDate(now(), 'America/New_York');