On 09/22/2018 10:00 PM, Alexander Korotkov wrote:
On Thu, Sep 20, 2018 at 3:52 PM Alexander Korotkov
<a.korot...@postgrespro.ru> wrote:
On Thu, Sep 20, 2018 at 6:09 AM amul sul <sula...@gmail.com> wrote:
Agreed, thanks for working on this.
Pushed, thanks.
Please, find attached patch improving documentation about
letters/digits in to_date()/to_timestamp() template string. I think
it needs review from native English speaker.
------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company
Hi Alexander,
I'm not a native speaker, but let me try to help. A new doc version is
attached.
--
Liudmila Mantrova
Technical writer at Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 9a7f683..1532bcc 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -6286,13 +6286,46 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
exceeds the number of separators in the template.
</para>
<para>
- If <literal>FX</literal> is specified, separator in template string
- matches to exactly one character in input string. Notice we don't insist
- input string character to be the same as template string separator.
+ If <literal>FX</literal> is specified, a separator in the template
+ string matches exactly one character in the input string. The
+ input string character does not need to be the same as the template
+ string separator.
For example, <literal>to_timestamp('2000/JUN', 'FXYYYY MON')</literal>
works, but <literal>to_timestamp('2000/JUN', 'FXYYYY MON')</literal>
- returns an error because a space second template string space consumed
- letter <literal>J</literal> from the input string.
+ returns an error because the second space in the template string
+ consumes letter <literal>J</literal> of the input string.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Template strings of <function>to_timestamp</function> and
+ <function>to_date</function> functions can also contain arbitrary
+ letters/digits between patterns. Such letters/digits can match
+ any characters in the input string. For example,
+ <literal>to_timestamp('2000yJUN', 'YYYYxMON')</literal> works.
+ </para>
+ <para>
+ Letters/digits consume an input string character only if the number
+ of extra characters at the beginning of the input string or between
+ the identified date/time values is less than or equal to the number
+ of the corresponding characters in the template string. This ensures
+ that the template string does not consume any characters of date/time
+ values when used without the <literal>FX</literal> option, even if
+ a letter/digit separator in the input string appears after a space.
+ For example, <literal>to_timestamp('2000y JUN', 'YYYYxMON')</literal>
+ works, but <literal>to_timestamp('2000 yJUN', 'YYYYxMON')</literal>
+ returns an error.
+ </para>
+ <para>
+ Note that if the template string contains an arbitrary letter,
+ the pattern that precedes this letter becomes greedy and tries
+ to match as many characters as possible. For example,
+ <literal>to_timestamp('2000906901', 'YYYYxMMxDD')</literal>
+ fails because the <literal>YYYY</literal> pattern matches
+ the whole input string instead of the first four characters.
+ Patterns separated by digits are non-greedy, so
+ <literal>to_timestamp('2000906901', 'YYYY0MM0DD')</literal> works fine.
</para>
</listitem>
