Re: pgsql: SQL/JSON query functions

Hi Andrew,

On Tue, Mar 29, 2022 at 08:57:37PM +0000, Andrew Dunstan wrote:
> SQL/JSON query functions
>
> This introduces the SQL/JSON functions for querying JSON data using
> jsonpath expressions. The functions are:
>
> JSON_EXISTS()
> JSON_QUERY()
> JSON_VALUE()
>
> All of these functions only operate on jsonb. The workaround for now is
> to cast the argument to jsonb.
>
> JSON_EXISTS() tests if the jsonpath expression applied to the jsonb
> value yields any values. JSON_VALUE() must return a single value, and an
> error occurs if it tries to return multiple values. JSON_QUERY() must
> return a json object or array, and there are various WRAPPER options for
> handling scalar or multi-value results. Both these functions have
> options for handling EMPTY and ERROR conditions.

Some of the tests introduced in this commit are a bit unstable when
run through a primary/standby setup. conchuela has showed one failure
today:
https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=conchuela&dt=2022-04-02%2002%3A36%3A03

Thanks,
--
Michael