Horton

Re: [HACKERS] Bug in to_timestamp().

Alexander Korotkov <a.korotkov@postgrespro.ru>

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From: Alexander Korotkov <a.korotkov@postgrespro.ru>
To: Artur Zakirov <a.zakirov@postgrespro.ru>
Cc: "David G. Johnston" <david.g.johnston@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, Dmitry Dolgov <9erthalion6@gmail.com>, Robert Haas <robertmhaas@gmail.com>, Thomas Munro <thomas.munro@enterprisedb.com>, amul sul <sulamul@gmail.com>, Pavel Stehule <pavel.stehule@gmail.com>, Alex Ignatov <a.ignatov@postgrespro.ru>, Bruce Momjian <bruce@momjian.us>, amul sul <sul_amul@yahoo.co.in>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2018-08-02T18:06:20Z
Lists: pgsql-hackers 
On Thu, Aug 2, 2018 at 6:17 PM Alexander Korotkov
<a.korotkov@postgrespro.ru> wrote:
> After some experiments I found that when you mix spaces and separators
> between two fields, then Oracle takes into account only length of last
> group of spaces/separators.
>
> # SELECT to_timestamp('2018- -01 02', 'YYYY----   --- --MM-DD') FROM
> dual2018-01-01 00:00:00 -10:00
> (length of last spaces/separators group is 2)
>
> # SELECT to_timestamp('2018- -01 02', 'YYYY----   --- --MM-DD') FROM dual
> 2018-01-01 00:00:00 -10:00
> (length of last spaces/separators group is 3)
>
> # SELECT to_timestamp('2018- -01 02', 'YYYY----   -- ---MM-DD') FROM dual
> 02.01.2018 00:00:00
> (length of last spaces/separators group is 2)

Ooops... I'm sorry, but I've posted wrong results here.  Correct
version is here.

# SELECT to_timestamp('2018- -01 02', 'YYYY----   --- --MM-DD') FROM dual
ORA-01843: not a valid month
(length of last spaces/separators group is 2)

# SELECT to_timestamp('2018- -01 02', 'YYYY----   -- ---MM-DD') FROM dual
02.01.2018 00:00:00
(length of last spaces/separators group is 3)

So length of last group of spaces/separators in the pattern should be
greater or equal to length of spaces/separators in the input string.
Other previous groups are ignored in Oracle.  And that seems
ridiculous for me.

------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company

Commits

  1. Improve behavior of to_timestamp()/to_date() functions

  2. Implement TZH and TZM timestamp format patterns

  3. as attache of this mail is patch (to the main tree) with to_char's