Re: to_date_valid()

On 8/15/16 7:33 AM, Andreas 'ads' Scherbaum wrote:
> postgres=# SELECT to_date('2011 12 18', 'YYYY MM DD');
> to_date
> ------------
> 2011-12-08
> (1 row)
>
>
> That is from the regression tests, and obviously handles the date
> transformation wrong. My attempt catches this, because I compare the
> date with the input date, and do not rely on a valid date only.

It's debatable what is correct here.

Using to_number, the behavior appears to be that a space in the pattern
ignores one character. For example:

test=# select to_number('123 456', '999 999');
to_number
-----------
123456

test=# select to_number('123 456', '999 999');
to_number
-----------
12356

Considering that, the above to_date result is not incorrect.

So just squashing the spaces and converting the value back is not a
correct approach to detecting overflow.

I think using ValidateDate() was the right idea. That is what we use
for checking date validity everywhere else.

--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services