Re: jsonb subscript operator returns null when key is fetched from table - Mailing list pgsql-bugs

From David G. Johnston
Subject Re: jsonb subscript operator returns null when key is fetched from table
Date
Msg-id CAKFQuwaKHLG5cPPmeoE0uYu5MYrHkwxhH1LV9aE0QrcDk0GnpA@mail.gmail.com
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Responses Re: jsonb subscript operator returns null when key is fetched from table
List pgsql-bugs
On Fri, Dec 9, 2022 at 1:35 PM exe-dealer <exe-dealer@yandex.ru> wrote:
jsonb subscript operator returns null when key is fetched from table.
 
PostgreSQL 15.1 on x86_64-pc-linux-musl, compiled by gcc (Alpine 12.2.1_git20220924-r4) 12.2.1 20220924, 64-bit
 
WITH cte AS MATERIALIZED (SELECT 'foo' k, '{"foo":"bar"}'::jsonb j)
SELECT j[k], j[k || ''] FROM cte;
 
-- returns
-- null, "bar"
 
-- expected
-- "bar", "bar"

Thanks for the report.  I can confirm that this is a problem in both v14 and v15.

To clarify the subject line - the issue manifests only if the CTE is MATERIALIZED.

Someone more experienced than I will need to actually do the debugging work though; hoping this reply will be seen by one of them.

David J.

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