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* BUG #17676: Text comparison appears to be wrong
@ 2022-11-03 19:54 PG Bug reporting form <noreply@postgresql.org>
0 siblings, 1 reply; 2+ messages in thread
From: PG Bug reporting form @ 2022-11-03 19:54 UTC (permalink / raw)
To: pgsql-bugs@lists.postgresql.org; +Cc: robj@hightouchinc.com
The following bug has been logged on the website:
Bug reference: 17676
Logged by: Rob Johnson
Email address: robj@hightouchinc.com
PostgreSQL version: 14.5
Operating system: Ubuntu
Description:
No tables are needed. Just ran this, comparing strings with lower-case 'x'
and period '.' characters. The first two columns are false as expected, the
last column is true, which appears to be wrong.
=> select '.' > 'x' as first, '.x' > 'x.' as second, '.xx' > 'x..' as third;
first | second | third
-------+--------+-------
f | f | t
(1 row)
My Postgres version:
=> select version();
version
---------------------------------------------------------------------------------------------------------------------------------
PostgreSQL 14.5 (Ubuntu 14.5-0ubuntu0.22.04.1) on x86_64-pc-linux-gnu,
compiled by gcc (Ubuntu 11.2.0-19ubuntu1) 11.2.0, 64-bit
(1 row)
I am located in the United States and haven't done anything to change
character sets, collations, or anything like that. The \l+ psql command
shows this for my database, which is called nigeldb:
=> \l+ nigeldb
List of databases
Name | Owner | Encoding | Collate | Ctype | Access
privileges | Size | Tablespace | Description
---------+----------+----------+-------------+-------------+-------------------+-------+------------+-------------
nigeldb | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 |
| 48 MB | pg_default |
(1 row)
^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: BUG #17676: Text comparison appears to be wrong
@ 2022-11-03 20:12 David G. Johnston <david.g.johnston@gmail.com>
parent: PG Bug reporting form <noreply@postgresql.org>
0 siblings, 0 replies; 2+ messages in thread
From: David G. Johnston @ 2022-11-03 20:12 UTC (permalink / raw)
To: robj@hightouchinc.com; pgsql-bugs@lists.postgresql.org
On Thu, Nov 3, 2022 at 12:56 PM PG Bug reporting form <
noreply@postgresql.org> wrote:
> The following bug has been logged on the website:
>
> Bug reference: 17676
> Logged by: Rob Johnson
> Email address: robj@hightouchinc.com
> PostgreSQL version: 14.5
> Operating system: Ubuntu
> Description:
>
> No tables are needed. Just ran this, comparing strings with lower-case 'x'
> and period '.' characters. The first two columns are false as expected,
> the
> last column is true, which appears to be wrong.
>
> => select '.' > 'x' as first, '.x' > 'x.' as second, '.xx' > 'x..' as
> third;
>
> List of databases
> Name | Owner | Encoding | Collate | Ctype | Access
> privileges | Size | Tablespace | Description
>
> ---------+----------+----------+-------------+-------------+-------------------+-------+------------+-------------
> nigeldb | postgres | UTF8 | en_US.UTF-8 | en_US.UTF-8 |
>
> | 48 MB | pg_default |
>
>
Not a bug.
This just seems to be how UTF-8 Collation works; punctuation produces
non-obvious sorting outcomes.
https://superuser.com/questions/227925/in-utf-8-collation-why-11-is-less-then-1
I confirmed that explicitly adding COLLATE "C" produces the expected
outcome for third.
David J.
^ permalink raw reply [nested|flat] 2+ messages in thread
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