On Wed, Sep 19, 2018 at 1:38 PM amul sul <sulamul@gmail.com> wrote: > On Wed, Sep 19, 2018 at 3:51 PM amul sul <sulamul@gmail.com> wrote: > > > > On Wed, Sep 19, 2018 at 2:57 PM Alexander Korotkov > [...] > > > > With this patch, to_date and to_timestamp behaving differently, see this: > > > > edb=# SELECT to_date('18 12 2011', 'xDDxMMxYYYY'); > > to_date > > -------------------- > > 18-DEC-11 00:00:00 > > (1 row) > > > > edb=# SELECT to_timestamp('18 12 2011', 'xDDxMMxYYYY'); > > to_timestamp > > --------------------------- > > 08-DEC-11 00:00:00 -05:00 <=========== Incorrect output. > > (1 row) > > > Sorry, this was wrong info -- with this patch, I had some mine trial changes. > > Both to_date and to_timestamp behaving same with your patch -- the > wrong output, we are expecting that? > > postgres =# SELECT to_date('18 12 2011', 'xDDxMMxYYYY'); > to_date > ------------ > 2011-12-08 > (1 row) >ma > postgres =# SELECT to_timestamp('18 12 2011', 'xDDxMMxYYYY'); > to_timestamp > ------------------------ > 2011-12-08 00:00:00-05 > (1 row)
It's hard to understand whether it was expected, because it wasn't properly documented. More important that it's the same behavior we have before cf984672, and purpose of cf984672 was not to change this.
But from the code comments, it's intentional. If you put digits or text characters into format string, you can skip non-separator input string characters. For instance you may do.
So, letters in format string doesn't allow you to extract fields at particular positions of digit sequence, but digits in format string allows you to. That's rather undocumented, but from the code you can get that it's intentional. Thus, I think it would be nice to improve the documentation here. But I still propose to commit the patch I propose to bring back unintentional behavior change in cf984672.