Re: isnull

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От Bruce Momjian
Тема Re: isnull
Дата
Msg-id 200003310143.UAA03317@candle.pha.pa.us
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Ответ на Re: isnull  (Joseph Shraibman <jks@p1.selectacast.net>)
Список pgsql-sql
> Julie Hunt wrote:
> 
> > Yes, you're right.  I remember attempting to do an outer left join using the
> > nullif but without success so I used the case function instead with success.
> > Maybe someone else knows more about nullif and why it doesn't seem to work.
> >
> > Regards,
> > Julie
> >
> 
> I've actually taken a closer look at the web page and not only did the name change,
> but I now notice that they change what it is supposed to do as well.  It does work
> as currently defined, but I needed something that does what the original
> documentation said:
> 
> IFNULL(input,non-NULL substitute)
>  return second argument if first is NULL
>  Example:        IFNULL(c1, 'N/A')
> 

New function is COALESCE.  It returns the first non-null argument.

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