Обсуждение: BUG #4739: strange behavior of EXTRACT(quarter from INTERVAL)

The following bug has been logged online:

Bug reference:      4739
Logged by:          Roman Kononov
Email address:      kononov@ftml.net
PostgreSQL version: 8.3.7
Operating system:   GNU/Linux x86_64
Description:        strange behavior of EXTRACT(quarter from INTERVAL)
Details:

test=# select month, extract(quarter from (month::varchar || '
month')::interval) from tbl;
 month | date_part
-------+-----------
    -6 |        -1
    -5 |         0
    -4 |         0
    -3 |         0
    -2 |         1
    -1 |         1
     0 |         1
     1 |         1
     2 |         1
     3 |         2
     4 |         2
     5 |         2
     6 |         3
(13 rows)

"Roman Kononov" <kononov@ftml.net> writes:
> Description:        strange behavior of EXTRACT(quarter from INTERVAL)

Somehow I can't get excited about the definition of EXTRACT(quarter)
for zero or negative intervals.  If you have an actual use-case for
this, what do you think it should do?

            regards, tom lane

On 2009-03-28 11:34 Tom Lane said the following:
> If you have an actual use-case for this, what do you think it should do?

I don't have a use-case (other than hypothetical "how many more years
and quarters did it take to complete this particular software project
than that particular project"). I think that a quarter is 1/4 year and
that is it.

Regards,

Roman

Roman Kononov <kononov@ftml.net> writes:
> On 2009-03-28 11:34 Tom Lane said the following:
>> If you have an actual use-case for this, what do you think it should do?

> I don't have a use-case (other than hypothetical "how many more years
> and quarters did it take to complete this particular software project
> than that particular project"). I think that a quarter is 1/4 year and
> that is it.

That's not really helpful for determining which way to round fractions.
I think we'll leave this alone until someone has a real use-case that
can guide the decision.

            regards, tom lane