On Wednesday, March 5, 2025, Shay Rojansky <
roji@roji.org> wrote:
SELECT JSON_VALUE(jsonb '"AQID"', '$' RETURNING bytea); -- Expected 0x010203, got AQID
I get \x41514944 which is precisely what I would expect since it what this query results in as well:
select 'AQID'::bytea;
If the behavior of RETURNING is meant to be identical to that of simply applying a cast, is there any actual advantage in using JSON_VALUE with RETURNING? In other words, why not just do JSON_VALUE(json '"AQID"', '$')::bytea instead of using RETURNING? I thought the point was precisely for RETURNING to be able to perform JSON-specific conversions (e.g. take into account that the base64 is being converted from a *JSON* string, and therefore apply base64 decoding to it).
Not really…it does seem to just be syntactic sugar. Not that we’d be likely to assume the contents of a JSON string are a base64 encoding as it is just, as you claim, a de-facto standard. Unless we have some standard (namely the one defining json_value) telling us that the contents are indeed always base64 encoded data we’ll just assume it’s plain text and act accordingly - in this case passing it into bytea’s input function.
David J.
