> This is not entirely correct.  PostgreSQL uses ? in operator names.
> There is even a predefined ? operator for JSON types:
>
> fw=> SELECT '{"a":true}'::jsonb ? 'a';
>   ?column?
> ----------
>   t
> (1 row)

More proof that every text-based programming language is on a mission to
colonize the entire ASCII range. And Unicode operators are slowly making
inroads.