Re: BUG #13768: JSONB concat

awasarax@yandex.ru writes:
> if "d" is null then return = null
> else
> return <> null

> CREATE OR REPLACE FUNCTION userfunc(jsonb)
>   RETURNS jsonb AS
> $BODY$
> DECLARE
>  r jsonb = null;
>  d jsonb = null;
> BEGIN
>  SELECT to_json(users.*) INTO r FROM users WHERE ///////; 
>  RETURN r||d; -- return null
> END;
> $BODY$
>   LANGUAGE plpgsql VOLATILE; 


I see nothing particularly wrong here.  There is long-established
precedent, eg, 'foo'::text || NULL is null too.  It makes sense
if you consider that NULL means "unknown".

			regards, tom lane