On Thursday, 11 August 2016 3:18 PM, Artur Zakirov <a.zaki...@postgrespro.ru> 
>Here is my patch. It is a proof of concept.>Date/Time 
>Formatting>-------------------->There are changes in date/time formatting 
>rules:-> now to_timestamp() and to_date() skip spaces in the input string and 
>>in the formatting string unless FX option is used, as Amul Sul wrote on 
>>first message of this thread. But Ex.2 gives an error now with this >patch 
>(should we fix this too?).
Why not, currently we are skipping whitespace exists at the start of input 
string but not if in format string.
[Skipped… ]
>Of course this patch can be completely wrong. But it tries to introduce >more 
>formal rules for formatting.>I will be grateful for notes and remarks.
Following are few scenarios where we break existing behaviour:
SELECT TO_TIMESTAMP('2015-12-31 13:43:36', 'YYYY MM DD HH24 MI SS');SELECT 
TO_TIMESTAMP('2011$03!18 23_38_15', 'YYYY-MM-DD HH24:MI:SS');SELECT 
TO_TIMESTAMP('2011*03*18 23^38&15', 'YYYY-MM-DD HH24:MI:SS');SELECT 
TO_TIMESTAMP('2011*03!18 #%23^38$15', 'YYYY-MM-DD$$$HH24:MI:SS');
But current patch behaviour is not that much bad either at least we have 
errors, but I am not sure about community acceptance.
I would like to divert communities' attention on following case:SELECT 
TO_TIMESTAMP('2013--10-01', 'YYYY-MM-DD');
Where the hyphen (-) is not skipped. So ultimately -10 is interpreted using MM 
as negative 10. So the date goes back by that many months (and probably 
additional days because of -31), and so the final output becomes 2012-01-30. 
But the fix is not specific to hyphen case. Ideally the fix would have been to 
handle it in from_char_parse_int(). Here, -10 is converted to int using strtol. 
May be we could have done it using strtoul(). Is there any intention behind not 
considering signed integers versus unsigned ones ?
Another is, shouldn’t we have error in following cases? SELECT 
TO_TIMESTAMP('2016-06-13 99:99:99', 'YYYY-MM-DD HH24:MI:SS'); SELECT 
TO_TIMESTAMP('2016-02-30 15:43:36', 'YYYY-MM-DD HH24:MI:SS');

Thanks  & Regards,Amul Sul

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