| Lists: | PostgreSQL : PostgreSQL 메일 링리스트 : 2008-02-13 이후 PGSQL 사설 토토 사이트 09:53 |
|---|
| From: | "Renaud Diez" <rdiez(at)salesprize(dot)com> |
|---|---|
| To: | pgsql-bugs(at)postgresql(dot)org |
| Subject: | BUG #3959: Huge calculation error |
| Date: | 2008-02-13 09:53:57 |
| Message-ID: | 200802130953.m1D9rv00042872@wwwmaster.postgresql.org |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Lists: | PostgreSQL : PostgreSQL 메일 링리스트 : 2008-02-13 이후 PGSQL 사설 토토 사이트 09:53 |
The following bug has been logged online:
Bug reference: 3959
Logged by: Renaud Diez
Email address: rdiez(at)salesprize(dot)com
PostgreSQL version: 8.2
Operating system: Debian
Description: Huge calculation error
Details:
the basic mathematical expression like the following one doesn't compute the
correct result:
> select 100*(1+(21/100));
return a result of 100 instead of 121.
| From: | Magnus Hagander <magnus(at)hagander(dot)net> |
|---|---|
| To: | Renaud Diez <rdiez(at)salesprize(dot)com> |
| Cc: | pgsql-bugs(at)postgresql(dot)org |
| Subject: | Re: BUG #3959: Huge calculation error |
| Date: | 2008-02-13 11:24:13 |
| Message-ID: | 47B2D35D.1000806@hagander.net |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Lists: | pgsql-bugs |
Renaud Diez wrote:
> The following bug has been logged online:
>
> Bug reference: 3959
> Logged by: Renaud Diez
> Email address: rdiez(at)salesprize(dot)com
> PostgreSQL version: 8.2
> Operating system: Debian
> Description: Huge calculation error
> Details:
>
> the basic mathematical expression like the following one doesn't compute the
> correct result:
>
>> select 100*(1+(21/100));
>
> return a result of 100 instead of 121.
It does compute the correct result, because you're doing integer
calculations. 21/100 for integers is 0. To make it do float calc, you can do
select 100*(1+(21::float/100));
Or you can do
select 100*(1+(21.0/100));
which will force it to numeric.
//Magnus
| From: | "Heikki Linnakangas" <heikki(at)enterprisedb(dot)com> |
|---|---|
| To: | "Renaud Diez" <rdiez(at)salesprize(dot)com> |
| Cc: | <pgsql-bugs(at)postgresql(dot)org> |
| Subject: | Re: BUG #3959: Huge calculation error |
| Date: | 2008-02-13 11:24:49 |
| Message-ID: | 47B2D381.1010304@enterprisedb.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Lists: | pgsql-bugs |
Renaud Diez wrote:
> The following bug has been logged online:
>
> Bug reference: 3959
> Logged by: Renaud Diez
> Email address: rdiez(at)salesprize(dot)com
> PostgreSQL version: 8.2
> Operating system: Debian
> Description: Huge calculation error
> Details:
>
> the basic mathematical expression like the following one doesn't compute the
> correct result:
>
>> select 100*(1+(21/100));
>
> return a result of 100 instead of 121.
That's because 21/100 = 0, in integer math. Try "SELECT
100*(1+(21/100.0))" to use floating points.
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
| From: | Rodriguez Fernando <rodriguez(at)ort(dot)edu(dot)uy> |
|---|---|
| To: | Renaud Diez <rdiez(at)salesprize(dot)com> |
| Cc: | pgsql-bugs(at)postgresql(dot)org |
| Subject: | Re: BUG #3959: Huge calculation error |
| Date: | 2008-02-13 15:02:34 |
| Message-ID: | 47B3068A.6000906@ort.edu.uy |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Lists: | pgsql-bugs |
Renaud Diez wrote:
> The following bug has been logged online:
>
> Bug reference: 3959
> Logged by: Renaud Diez
> Email address: rdiez(at)salesprize(dot)com
> PostgreSQL version: 8.2
> Operating system: Debian
> Description: Huge calculation error
> Details:
>
> the basic mathematical expression like the following one doesn't compute the
> correct result:
>
>
>> select 100*(1+(21/100));
>>
>
> return a result of 100 instead of 121.
>
> ---------------------------(end of broadcast)---------------------------
> TIP 6: explain analyze is your friend
>
>
Hola, en realidad no lo hace mal, no es lo que esprabas, lo que en
realidad necesitas es esto:
select 100*(1+(21.0/100))::float;
saludos Fernando