Re: coalesce for null AND empty strings

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От Ferdinand Gassauer
Тема Re: coalesce for null AND empty strings
Дата
Msg-id 200703301354.22221.gassauer@kde.org
обсуждение исходный текст
Ответ на Re: coalesce for null AND empty strings  (Richard Huxton <dev@archonet.com>)
Список pgsql-general
On Friday 30 March 2007 10:19:35 Richard Huxton wrote:
> Don't forget to cc: the list!

snip
> > OK this shortens the function, but does not help to "solve"  the coalesce
> > problem
> > coalecse(empty2null(var1),empty2null(var2),....empty2null(var-n))
> > instead of
> > coalecse2(var1,var2,...var-n)
> >
> > where the empty2null is doing it's job "inside" the coalesce.
>
> Well, you can always write the four or five variations you want:
> CREATE OR REPLACE FUNCTION coalesce_and_blank(varchar) ...
> CREATE OR REPLACE FUNCTION coalesce_and_blank(varchar,varchar) ...
> CREATE OR REPLACE FUNCTION coalesce_and_blank(varchar,varchar,varchar) ...
OK - this is a solution I didn't think off , because other system do not allow
this sort of "overloading".

Nevertheless I think
* coalesce takes n arguments, which would need the user to write n functions
to fully cover the functionality - even though I think it's seldom to have
more than 4-5 arguments.
* looking through Google it IS a concern for many others and thus this
function should be distributed as default.


--
cu
ferdinand

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