Re: temporal version of generate_series()

2008/5/1 H. Harada <umi.tanuki@gmail.com>:
> 2008/5/1 Pavel Stehule <pavel.stehule@gmail.com>:
>
> > Hello
>  >
>  >  why you don't use polymorphic types?
>  Ah, good idea. I didn't think we could fix the third argument to
>  "interval" but "anyelement".
>  For a temporal version, it's reasonable.

I was thinking about it again. There are 3 points:

a. It will get complicated in the function to resolve operator for
polymorphic types, including search for namespace and error (not
found) handling.
b. Other temporal data types than timestamp is easy to be casted from
timestamp results.
c. In the integer version of generate_series also it is possible to
cast the results to other numerical types though harder to cast them
to temporal data types.

So it would be better to keep current patch, isn't it?


postgres=# select generate_series('2008/05/01 20:00'::timestamp,
'2008/05/02 08:00'::timestamp
, '1 hour'::interval);
   generate_series
---------------------
 2008-05-01 20:00:00
 2008-05-01 21:00:00
 2008-05-01 22:00:00
 2008-05-01 23:00:00
 2008-05-02 00:00:00
 2008-05-02 01:00:00
 2008-05-02 02:00:00
 2008-05-02 03:00:00
 2008-05-02 04:00:00
 2008-05-02 05:00:00
 2008-05-02 06:00:00
 2008-05-02 07:00:00
 2008-05-02 08:00:00
(13 rows)

postgres=# select generate_series('2008/05/01 20:00'::timestamp,
'2008/05/02 08:00'::timestamp
, '1 hour'::interval)::time;
 generate_series
-----------------
 20:00:00
 21:00:00
 22:00:00
 23:00:00
 00:00:00
 01:00:00
 02:00:00
 03:00:00
 04:00:00
 05:00:00
 06:00:00
 07:00:00
 08:00:00
(13 rows)

postgres=# select generate_series('2008/05/01 20:00'::timestamp,
'2008/05/02 08:00'::timestamp
, '1 hour'::interval)::timestamptz;
    generate_series
------------------------
 2008-05-01 20:00:00+09
 2008-05-01 21:00:00+09
 2008-05-01 22:00:00+09
 2008-05-01 23:00:00+09
 2008-05-02 00:00:00+09
 2008-05-02 01:00:00+09
 2008-05-02 02:00:00+09
 2008-05-02 03:00:00+09
 2008-05-02 04:00:00+09
 2008-05-02 05:00:00+09
 2008-05-02 06:00:00+09
 2008-05-02 07:00:00+09
 2008-05-02 08:00:00+09
(13 rows)

postgres=# select generate_series('2008/05/01 20:00'::timestamp,
'2008/05/02 08:00'::timestamp
, '1 hour'::interval)::date;
 generate_series
-----------------
 2008-05-01
 2008-05-01
 2008-05-01
 2008-05-01
 2008-05-02
 2008-05-02
 2008-05-02
 2008-05-02
 2008-05-02
 2008-05-02
 2008-05-02
 2008-05-02
 2008-05-02
(13 rows)


Hitoshi Harada

2008/5/1 H. Harada <umi.tanuki@gmail.com>:
> 2008/5/1 Pavel Stehule <pavel.stehule@gmail.com>:
>
> > Hello
>  >
>  >  why you don't use polymorphic types?
>  Ah, good idea. I didn't think we could fix the third argument to
>  "interval" but "anyelement".
>  For a temporal version, it's reasonable.
>
>  Also, the name "generate_time_series" is better than before?
>
>  Hitoshi Harada
>
>
>  2008/5/1 Pavel Stehule <pavel.stehule@gmail.com>:
>
>
> > Hello
>  >
>  >  why you don't use polymorphic types?
>  >
>  >  like:
>  >
>  >  create or replace function generate_time_series(anyelement,
>  >  anyelement, interval, OUT result anyelement)
>  >  returns setof anyelement as $$
>  >  begin
>  >   result := $1;
>  >   while (result <= $2) loop
>  >     return next;
>  >     result := result + $3;
>  >   end loop;
>  >   return;
>  >  end;
>  >  $$ language plpgsql;
>  >
>  >  Regards
>  >  Pavel Stehule
>  >
>  >
>  >
>  >  2008/5/1 H. Harada <umi.tanuki@gmail.com>:
>  >
>  >
>  > > Here's the sync and updated patch.
>  >  > It contains "strict" in catalog as well.
>  >  >
>  >  > Hitoshi Harada
>  >  >
>  >  > 2008/4/24 H. Harada <umi.tanuki@gmail.com>:
>  >  >> 2008/4/23 Alvaro Herrera <alvherre@commandprompt.com>:
>  >  >>
>  >  >> > H.Harada escribió:
>  >  >>  >
>  >  >>  >
>  >  >>  >  > # This is my first time to send a patch. If I did something wrong, I
>  >  >>  >  > appreciate your pointing me out.
>  >  >>  >
>  >  >>  >  Brace positioning is off w.r.t. our conventions -- please fix that and
>  >  >>  >  resubmit.
>  >  >>
>  >  >>  Here's updated version. Thanks for your advice.
>  >  >>
>  >  >>  Hitoshi Harada
>  >  >>
>  >  >>  2008/4/23 Alvaro Herrera <alvherre@commandprompt.com>:
>  >  >>
>  >  >>
>  >  >> > H.Harada escribió:
>  >  >>  >
>  >  >>  >
>  >  >>  >  > # This is my first time to send a patch. If I did something wrong, I
>  >  >>  >  > appreciate your pointing me out.
>  >  >>  >
>  >  >>  >  Brace positioning is off w.r.t. our conventions -- please fix that and
>  >  >>  >  resubmit.
>  >  >>  >
>  >  >>  >  I have added this patch to the May commitfest.
>  >  >>  >
>  >  >>  >  --
>  >  >>  >  Alvaro Herrera                                http://www.CommandPrompt.com/
>  >  >>  >  The PostgreSQL Company - Command Prompt, Inc.
>  >  >>  >
>  >  >>
>  >  >
>  >  >
>  >  > --
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