select generate_series('2020-01-01'::date , '2020-12-31'::date, '1 day'::interval)::date
SELECT to_char(GENERATE_SERIES(to_date('2020-01-01','YYYY-MM-DD'), to_date('2020-12-31','YYYY-MM-DD'), '1 day'::INTERVAL)::DATE, 'YYYY-MM-DD') AS date
참고문서 https://dzzienki.tistory.com/73