Convert a Julian day to a date
A
Julian Day can be converted to a date with the
'J' format specifier:
select
to_date(2459496, 'J') -- October 8th, 2021
from
dual;
Oracle counts the inexisting year 0. Thus, Julian days before the Year 1 are inconsistent with other Julian days:
select
to_date(1721424, 'J'), -- 0001-01-01
to_date(1721057, 'J') -- -0001-12-31
from
dual;
The following select statement returns Oracle's earliest date it can process (-4712-01-01). (Note that due to Oracle's special Year-0 counting, the first Julian day is actually -4713-01-01).
select to_date(1, 'J') from dual;