Feature Request: Support all JSON extension functions

[rchui]

Even though you can install the JSON extension on duckdb, set it to enabled, and the documentation states that the JSON extension is supported by pg_duckdb not all functions are supported. Notably the JSON agg functions are not supported in pg_duckdb and will result in a query error.

SELECT duckdb.install_extension('json');
UPDATE duckdb.extensions SET enabled = true WHERE name = 'json';

Attempting to run a query with json_object_array

select json_object_array(...) from ddb$

Results in an error

Query 1 ERROR at Line 5: : ERROR:  function json_object_array(record) does not exist
LINE 1: select json_object_array(items) from (select * from ddb$...
               ^
HINT:  No function matches the given name and argument types. You might need to add explicit type casts.

[JelteF]

Some discussion about this is also happening here: #516

[ritwizsinha]

@rchui what function is json_object_array. I don't see it in the documentation