Re: BUG #1871: operations with data types

Added to TODO:

    o Fix SELECT INTERVAL '1' MONTH;

---------------------------------------------------------------------------

Tom Lane wrote:
> Michael Fuhr <mike@fuhr.org> writes:
> > I just noticed something in PostgreSQL that might be considered
> > surprising (although I do see "Add ISO INTERVAL handling" in the
> > TODO list):
>
> >   test=> select interval '1' month;
> >    interval
> >   ----------
> >    00:00:00
> >   (1 row)
>
> > What's the parser doing here?
>
> Not getting it right ;-).  Trying this in historical versions is
> amusing:
>
> 7.0:
> regression=# select interval '1' month;
> ERROR:  parser: parse error at or near "month"
>
> 7.1:
> regression=# select interval '1' month;
> ERROR:  Bad interval external representation '1'
>
> 7.2:
> regression=# select interval '1' month;
>  interval
> ----------
>  00:00
> (1 row)
>
> 7.3:
> regression=# select interval '1' month;
>  interval
> ----------
>  00:00:01
> (1 row)
>
> 7.4 and up:
> regression=# select interval '1' month;
>  interval
> ----------
>  00:00:00
> (1 row)
>
> What is happening in the current versions is that coerce_type thinks
> it can coerce the literal string to interval without supplying the
> modifier, and then use interval_scale() to apply the typmod.  This
> works OK for most of the data types, but not for interval it seems...
>
> Basically the support for these weird syntaxes is something that Tom
> Lockhart never finished, and no one has bothered to pick up the work
> since he left the project.
>
>             regards, tom lane
>
> ---------------------------(end of broadcast)---------------------------
> TIP 3: Have you checked our extensive FAQ?
>
>                http://www.postgresql.org/docs/faq
>

--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073