coalesce for null AND empty strings

Hi!

it would be great to have a coalesce2 function which treats empty strings as
null values.

as far as I have seen, there are a lot of comments and coding solutions about
this, but none is an "easy" one and all make the code a bit more complicated
and more difficult to maintain.

I have created this function.
It's similar to nullif, but takes only ONE argument

create or replace function "empty2null"(text_i varchar)
returns varchar as $$
declare
text_p varchar;
begin
if text_i = ''
then text_p := null;
else text_p := text_i;
end if;
return text_p;
end;
$$ LANGUAGE plpgsql;

--
cu
Ferdinand