Re: [HACKERS] empty concatenate

>
> NULL's can not be concatenated, but '' can. Looks fine to me:
>
> ---------------------------------------------------------------------------
>
> test=> create table ff (x text, y text);
> insCREATE
> test=> insert into ff values ('a','');
> INSERT 19082 1
> test=> insert into ff values ('b',null);
> INSERT 19083 1
> test=> select x || y from ff;
> ?column?
> ----------
> a
>
> (2 rows)

Well, but why PgSQL ignore function result if any argument is NULL. IMHO is
function's problem what return, and PgSQL must use this result.

How can user write / use function which response on NULL (as IFNULL())?

Karel