Re: bug in date_part() function in 6.5.2, 7.0.2

> Sample Code
> create table oops (date date);
>
> insert into oops (date) values (to_date('24.03.2000','dd.mm.yyyy'));
> insert into oops (date) values (to_date('25.03.2000','dd.mm.yyyy'));
> insert into oops (date) values (to_date('26.03.2000','dd.mm.yyyy'));
> insert into oops (date) values (to_date('27.03.2000','dd.mm.yyyy'));
>
> select
>  date::date
> ,date_part('day',date::date)
> ,date_part('dow',date::date)
> from oops
> order by date;
>
>   ?column?  | date_part | date_part
> ------------+-----------+-----------
>  24.03.2000 |        24 |         5
>  25.03.2000 |        25 |         6
>  26.03.2000 |        25 |         6
>  27.03.2000 |        27 |         1
> (4 rows)

 Interesting...

test=# select date::timestamp, date_part('day', date), to_char(date, 'DD')
from oops;
        ?column?        | date_part | to_char
------------------------+-----------+---------
 2000-03-24 00:00:00+01 |        24 | 24
 2000-03-25 00:00:00+01 |        25 | 25
 2000-03-25 23:00:00+01 |        25 | 25
 2000-03-27 00:00:00+02 |        27 | 27
(4 rows)

 to_char() and date_part() has different code but some result, a problem
can't be in date_part()...

test=# select date::timestamp from oops;
        ?column?
------------------------
 2000-03-24 00:00:00+01
 2000-03-25 00:00:00+01
 2000-03-25 23:00:00+01
           ^^^^
           ????
 2000-03-27 00:00:00+02
(4 rows)

 ....it's not date_part() bug, it's to_date() bug:

test=# select to_date('26.03.2000','dd.mm.yyyy')::timestamp;
        ?column?
------------------------
 2000-03-25 23:00:00+01
            ^^^
           ! Bug !

test=# select to_timestamp('26.03.2000','dd.mm.yyyy');
      to_timestamp
------------------------
 2000-03-26 00:00:00+01
            ^^^
          ! correct !


 But to_date() call to_timestamp() only:

Datum
to_date(PG_FUNCTION_ARGS)
{
        /* Quick hack: since our inputs are just like to_timestamp,
         * hand over the whole input info struct...
         */
        return DirectFunctionCall1(timestamp_date, to_timestamp(fcinfo));
}

 Comments, some idea?

                Karel