I was about to do some date/time calculations as I got an unexpected result with the to_date-function.
select to_date('12:13', 'hh24:mi'), sysdate from dual 2020-09-01 12:13:00 2020-09-28 08:59:01
As I did the to_date-conversion, based only on the hour and minute pattern, the date is set to the first of the current month (the format is yyyy-mm-dd hh24:mi:ss). I was not expecting that.
The same applies when converting to timestamps:
select to_timestamp_tz('12:13', 'hh24:mi'), to_timestamp('12:13', 'hh24:mi') from dual; 2020-09-01 12:13:00.000000000 2020-09-01 12:13:00.000000000
So – if you’re, like me, planning on doing further calculations, be sure you know what your time or actually date, that is, is converted to.
(tested on Oracle 18c and 19c (19.0))