Re: boolean in caluclations

From: Michel Cadot <micadot{at}altern{dot}org>
Date: Wed, 30 May 2007 17:43:18 +0200
Message-ID: <465d9b94$0$32272$426a74cc@news.free.fr>

"Vladimir M. Zakharychev" <vladimir.zakharychev_at_gmail.com> a écrit dans le message de news: 1180500862.700175.262130_at_q69g2000hsb.googlegroups.com... On May 30, 8:35 am, "Michel Cadot" <micadot{at}altern{dot}org> wrote:
> "jobs" <j..._at_webdos.com> a écrit dans le message de news: 1180467609.765964.202..._at_p47g2000hsd.googlegroups.com...
> | how can i do this in pl-sql?
> |
> | when lines=2 that is replaced by a 1 allowing that math to take place
> |
> | when lines>2 it adds the other piece instead. Trying to avoid if
> | statements.
> |
> | fee := (fixed_mf + ((lines=2)* lines_2) +
> | (((lines>2)*(lines-1))*lines_more));
> |
> | thanks for any help or information.
> |
>
> (lines = 2) returns TRUE or FALSE.
> How can you multiply that by lines_2?
>
> What should be the result of 2*TRUE?
>
> Regards
> Michel Cadot

Twice as true as conventional TRUE? :) Seriously, the OP says that when lines=2, this should be replaced by 1 (in other words, ignored.) This can be done with a searched CASE:

fee := fixed_mf +
  CASE
   WHEN lines=2 THEN lines_2
   WHEN lines>2 THEN (lines-1)*lines_more   END; Hey, no IFs, just as the OP wanted! :)

Regards,

   Vladimir M. Zakharychev
   N-Networks, makers of Dynamic PSP(tm)    http://www.dynamicpsp.com

---

I understand what it means but there is no reason for TRUE to be 1. In C specifications, is TRUE any not 0 value? I worked in an OS where TRUE was xFFFFFFFFF, or was it FALSE I don't remember but both is valid.
What if Oracle choose to represent TRUE with 0 and FALSE with 1. I mean numeric operation upon boolean values is meaningless.

SQL> declare i integer;
  2 begin
  3 i := 1 +

  4         case
  5         when 1=2 then 1
  6         when 1=1 then 2
  7         end;

  8 dbms_output.put_line('i='||i);
  9 end;
 10 /
i=3

PL/SQL procedure successfully completed.

This works (as you said).

Regards
Michel Cadot Received on Wed May 30 2007 - 10:43:18 CDT