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* BUG #18222: Unexpected Error--Cannot delete from scalar
@ 2023-12-04 05:56 PG Bug reporting form <noreply@postgresql.org>
0 siblings, 2 replies; 4+ messages in thread
From: PG Bug reporting form @ 2023-12-04 05:56 UTC (permalink / raw)
To: pgsql-bugs@lists.postgresql.org; +Cc: bajinsheng@u.nus.edu
The following bug has been logged on the website:
Bug reference: 18222
Logged by: Jinsheng Ba
Email address: bajinsheng@u.nus.edu
PostgreSQL version: 16.1
Operating system: Ubuntu
Description:
SELECT ('1'-to_hex(2))::BOOLEAN; -- ERROR: cannot delete from scalar
This error looks strange to me as I do not understand what this error
means.
If I execute the following query, there is no error instead:
SELECT '1'-2; -- {-2}
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: BUG #18222: Unexpected Error--Cannot delete from scalar
@ 2023-12-04 13:50 Laurenz Albe <laurenz.albe@cybertec.at>
parent: PG Bug reporting form <noreply@postgresql.org>
1 sibling, 0 replies; 4+ messages in thread
From: Laurenz Albe @ 2023-12-04 13:50 UTC (permalink / raw)
To: bajinsheng@u.nus.edu; pgsql-bugs@lists.postgresql.org
On Mon, 2023-12-04 at 05:56 +0000, PG Bug reporting form wrote:
> PostgreSQL version: 16.1
>
> SELECT ('1'-to_hex(2))::BOOLEAN; -- ERROR: cannot delete from scalar
>
> This error looks strange to me as I do not understand what this error
> means.
>
> If I execute the following query, there is no error instead:
> SELECT '1'-2; -- {-2}
That's not a bug.
PostgreSQL infers the operator jsonb - text. '1' gives a valid "jsonb"
scalar, but you cannot remove an attribute from a JSON scalar.
I cannot tell you what to do, because your expression makes as little
sense to me as it does to PostgreSQL.
Yours,
Laurenz Albe
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: BUG #18222: Unexpected Error--Cannot delete from scalar
@ 2023-12-04 14:15 Tom Lane <tgl@sss.pgh.pa.us>
parent: PG Bug reporting form <noreply@postgresql.org>
1 sibling, 1 reply; 4+ messages in thread
From: Tom Lane @ 2023-12-04 14:15 UTC (permalink / raw)
To: bajinsheng@u.nus.edu; +Cc: pgsql-bugs@lists.postgresql.org
PG Bug reporting form <noreply@postgresql.org> writes:
> SELECT ('1'-to_hex(2))::BOOLEAN; -- ERROR: cannot delete from scalar
> This error looks strange to me as I do not understand what this error
> means.
Just out of curiosity, what did you expect that to do?
to_hex() produces type text, and there's no "text - text" operator.
What's evidently happening is that the parser finds "jsonb - text"
(i.e., jsonb_delete) as the only potentially applicable operator.
It successfully coerces '1' to a scalar jsonb value, but then
jsonb_delete() spits up because it's expecting an array.
I'm not sure that it was such a great idea to define '-' as having
this meaning for jsonb, but it's been there awhile now so probably
too late to change.
regards, tom lane
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: BUG #18222: Unexpected Error--Cannot delete from scalar
@ 2023-12-04 14:21 Ba Jinsheng <bajinsheng@u.nus.edu>
parent: Tom Lane <tgl@sss.pgh.pa.us>
0 siblings, 0 replies; 4+ messages in thread
From: Ba Jinsheng @ 2023-12-04 14:21 UTC (permalink / raw)
To: Tom Lane <tgl@sss.pgh.pa.us>; +Cc: pgsql-bugs@lists.postgresql.org <pgsql-bugs@lists.postgresql.org>
I thought it would probably give a warning that no available operator for text-text, not this error.
Anyway, thanks!
________________________________
From: Tom Lane <tgl@sss.pgh.pa.us>
Sent: Monday, December 4, 2023 10:15:46 PM
To: Ba Jinsheng <bajinsheng@u.nus.edu>
Cc: pgsql-bugs@lists.postgresql.org <pgsql-bugs@lists.postgresql.org>
Subject: Re: BUG #18222: Unexpected Error--Cannot delete from scalar
- External Email -
PG Bug reporting form <noreply@postgresql.org> writes:
> SELECT ('1'-to_hex(2))::BOOLEAN; -- ERROR: cannot delete from scalar
> This error looks strange to me as I do not understand what this error
> means.
Just out of curiosity, what did you expect that to do?
to_hex() produces type text, and there's no "text - text" operator.
What's evidently happening is that the parser finds "jsonb - text"
(i.e., jsonb_delete) as the only potentially applicable operator.
It successfully coerces '1' to a scalar jsonb value, but then
jsonb_delete() spits up because it's expecting an array.
I'm not sure that it was such a great idea to define '-' as having
this meaning for jsonb, but it's been there awhile now so probably
too late to change.
regards, tom lane
^ permalink raw reply [nested|flat] 4+ messages in thread
end of thread, other threads:[~2023-12-04 14:21 UTC | newest]
Thread overview: 4+ messages (download: mbox mbox.gz follow: Atom feed)
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2023-12-04 05:56 BUG #18222: Unexpected Error--Cannot delete from scalar PG Bug reporting form <noreply@postgresql.org>
2023-12-04 13:50 ` Laurenz Albe <laurenz.albe@cybertec.at>
2023-12-04 14:15 ` Tom Lane <tgl@sss.pgh.pa.us>
2023-12-04 14:21 ` Ba Jinsheng <bajinsheng@u.nus.edu>
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