Re: Extract numeric filed in JSONB more effectively

Hi:

>
> can confirm the patch's jsonb_object_field_numeric is faster than
> pg_catalog."numeric"(jsonb).
>

Thanks for the confirmation.

>
> This function is not easy to find out...
>
> select jsonb_numeric(jsonb'{"a":11}'->'a'); --fail
>

jsonb_numeric is a prosrc rather than a proname, that's why you
can't call them directly.

select * from pg_proc where prosrc = 'jsonb_numeric';
select * from pg_proc where proname = 'jsonb_numeric';

It is bound to "numeric"(jsonb) cast, so we can call it with
a->'a'::numeric.

select numeric('{"a":11}'->'a'); --fail.

> select "numeric"('{"a":11}'::jsonb->'a'); --ok
>

The double quotes look weird to me. but it looks like a common situation.

select numeric('1'::int); -- failed.
select "numeric"('1'::int); -- ok.

--
Best Regards
Andy Fan