SQL INTERVAL

What & Why

INTERVAL is its own data type representing a duration — INTERVAL '3 months', INTERVAL '1 year', INTERVAL '2 days'. Unlike plain integer arithmetic (which only ever means days), an interval can express units that don't have a fixed day count, and Postgres handles the calendar math correctly — adding a month to January 31st correctly lands on a real date, not an invalid one.

See How It Works

SELECT
  id,
  created_at,
  created_at + INTERVAL '7 days' AS activation_deadline,
  created_at + INTERVAL '2 hours' AS two_hours_later,
  created_at + INTERVAL '1 month' AS one_month_later
FROM growth.users
ORDER BY created_at, id;