pgsql-bugs(at)postgresql(dot)org writes:
> I have created an view. When I select fields separately all looks ok but when I try to select 3 fields for concatention (f1 || f2 || f3) the resul is empty when f3 is empty. I think it is not expected bahaviour.
That's the way NULLs are defined to work by the SQL specification.
There is a big difference between NULL and an empty string --- don't use
one when you mean the other.
regards, tom lane