Thomas Lockhart writes:
> The age() functions *preserve* the qualitative fields year and month. So
> you see the difference in results:
>
> lockhart=# select age('today', '1957-06-13');
> -------------------------
> 43 years 9 mons 28 days
>
> lockhart=# select timestamp 'today' - timestamp '1957-06-13';
> ------------
> 16008 days
>
> In the case for the DATE type, the result is an integer value (not an
> interval) which I believe was done intentionally but I'm not recalling
> exactly why; I can research it if necessary:
>
> lockhart=# select date 'today' - date '1957-06-13';
> ----------
> 16008
>
> returns the number of days (which is also an absolute, quantitative
> time).
ISTM that this is more a result of
a) timestamp subtraction not implemented per spec
b) date substraction not implemented at all (it does date - integer)
c) implicit type conversions running wild
d) intervals not implemented per spec
(spec == SQL). Lots of fun projects here... ;-)
--
Peter Eisentraut peter_e@gmx.net http://yi.org/peter-e/