Re: Null Conversion

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От Stephan Szabo
Тема Re: Null Conversion
Дата
Msg-id Pine.BSF.4.21.0108142137160.72144-100000@megazone23.bigpanda.com
обсуждение исходный текст
Ответ на Re: Null Conversion  (Mike Withers <M.withers@uws.edu.au>)
Список pgsql-general
On Wed, 15 Aug 2001, Mike Withers wrote:

> At 06:30 PM 8/14/01 -0700, you wrote:
> >On Wed, 15 Aug 2001, Mike Withers wrote:
> >
> >> Can anyone tell me how I might convert a null attribute value into a zero
> >> attribute value such that it can be multiplied in a query.
> >>
> >> In Oracle I could do:
> >>
> >> sal*12*NVL(COMM, 0) AS "Annual Income"
> >>
> >> where COMM is an attribute (a salesman commission, in an employes table)
> >> which has null values. This allows null commissions for non salesmen to
> >> give a zero calculated value. The NVL converts a null into zero.
> >
> >Try coalesce(COMM, 0)
> >
> Thanks, this works. Tried the other suggestion:
>
> sal * 12 * CAST(COMM AS float8) AS "Annual Income"
>
> which unfortunately didn't work.

Yeah, that'll still give you a null out.  I guess oracle must have
done nvl before the standards group decided on coalesce for the name
of that.


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