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Re: to_date() and to_timestamp() with negative years

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On 11/3/21 11:18, Bryn Llewellyn wrote:
tgl@xxxxxxxxxxxxx wrote:

Bryn Llewellyn <bryn@xxxxxxxxxxxx> writes:
Is there any chance that you might be bold and simply make negative "year" values illegal in "to_date()" and "to_timestamp()" — just as they already are in "make_timestamp()", "make_timestamptz()", and the "from text" typecasts to date-time moment values?

Uh, what?

regression=# select make_timestamp(-44,3,15,0,0,0);
     make_timestamp
------------------------
0044-03-15 00:00:00 BC
(1 row)

The other stuff you are talking about looks like confusion around which
characters are minus signs in the data and which ones are field
separators.  Given the very squishy definitions of to_date/to_timestamp,
I'm not surprised if that works only with carefully chosen field
layouts --- but it does work for me with all of these cases:

regression=# select to_date('-0044-03-15', 'YYYY-MM-DD');
    to_date
---------------
0044-03-15 BC
(1 row)

regression=# select to_date('03-15--0044', 'MM-DD-YYYY');
    to_date
---------------
0044-03-15 BC
(1 row)

regression=# select to_date('03/15/-0044', 'MM/DD/YYYY');
    to_date
---------------
0044-03-15 BC
(1 row)

I'd be the first to agree that that code is a mess and could stand to
be rewritten --- but I seriously doubt that we'd take a patch that
intentionally breaks cases that work fine today.  There's also the
angle that these are supposed to be Oracle-compatible, so I wonder
what Oracle does with such input.

I just ran your test:

select make_timestamp(-44,3,15,0,0,0);

in each of the three environments that I mentioned—but especially, therefore, in PG 13.4 (on macOS).

It cased the error that I mentioned:

ERROR:  22008: date field value out of range: -44-03-15

It's the same with "make_timestamp()".

https://www.postgresql.org/docs/14/release-14.html#id-1.11.6.5.3

"
Allow make_timestamp()/make_timestamptz() to accept negative years (Peter Eisentraut)

Negative values are interpreted as BC years.
"

In what PG version did you run your test?

I'm not surprised that grandfathered-in "solution" that I described will never go away—despite its questionable conceptual basis.






--
Adrian Klaver
adrian.klaver@xxxxxxxxxxx





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