Re: BUG #14017: strange syntax error

anthony@arkia.nl writes:
> When running the create or replace function on the following I get this
> error

> ERROR:  syntax error at or near "("
> LINE 5: ...trim(isnull(new.straat,''::text) || ' ' || isnull (  new.hui...

ISNULL is a keyword; it's a short form of IS NULL.  It's only by pure
chance that you've ever been able to use this function:

> CREATE OR REPLACE FUNCTION public."isnull"(

without double-quoting its name everywhere.  The fact that it accidentally
worked in this context before 9.5, but fails now, probably has something
to do with the changes we made in 9.5 to give IS NULL the syntactic
precedence required by the SQL standard.

You could rename the function to something that doesn't conflict, like
"is_null".  But really my recommendation is to drop it entirely and use
COALESCE(), which does the same thing, is considerably more efficient,
and is SQL-standard.

            regards, tom lane