8.4.2015, 12:09, Björn Lundin kirjoitti:
Hi!
below are some commands to
replicate a strange sorting order.
I do not see why id:s 3-6 are in the middle of the result set.
What am I missing?
begin;
create table T_SORT (
ID bigint default 1 not null , -- Primary Key
NAME varchar(100) default ' ' not null
);
alter table T_SORT add constraint T_SORTP1 primary key (
ID
);
insert into T_SORT values ( 1,'FINISH_110_150_1');
insert into T_SORT values ( 2,'FINISH_110_200_1');
insert into T_SORT values ( 3,'FINISH_1.10_20.0_3');
insert into T_SORT values ( 4,'FINISH_1.10_20.0_4');
insert into T_SORT values ( 5,'FINISH_1.10_30.0_3');
insert into T_SORT values ( 6,'FINISH_1.10_30.0_4');
insert into T_SORT values ( 7,'FINISH_120_150_1');
insert into T_SORT values ( 8,'FINISH_120_200_1');
select * from T_SORT order by NAME ;
rollback;
id | name
----+--------------------
1 | FINISH_110_150_1
2 | FINISH_110_200_1
3 | FINISH_1.10_20.0_3
4 | FINISH_1.10_20.0_4
5 | FINISH_1.10_30.0_3
6 | FINISH_1.10_30.0_4
7 | FINISH_120_150_1
8 | FINISH_120_200_1
(8 rows)
why is FINISH_1.10_20.0_3 between
FINISH_110_200_1 and
FINISH_120_150_1
?
That is why is '.' between 1 and 2 as in 110/120 ?
pg_admin III reports the database is created like
CREATE DATABASE bnl
WITH OWNER = bnl
ENCODING = 'UTF8'
TABLESPACE = pg_default
LC_COLLATE = 'en_US.UTF-8'
LC_CTYPE = 'en_US.UTF-8'
CONNECTION LIMIT = -1;
bnl=> select version();
version
--------------------------------------------------------------------------------------------------------------
PostgreSQL 9.3.3 on x86_64-unknown-linux-gnu, compiled by gcc (GCC)
4.6.3 20120306 (Red Hat 4.6.3-2), 64-bit
(1 row)
psql says
psql (9.3.5, server 9.3.3)
It is an Amazon RDS-service
client machine
bnl@prod:~$ uname -a
Linux prod 3.2.0-4-amd64 #1 SMP Debian 3.2.63-2+deb7u1 x86_64 GNU/Linux
bnl@prod:~$ locale
LANG=en_US.UTF-8
LANGUAGE=
LC_CTYPE="en_US.UTF-8"
LC_NUMERIC="en_US.UTF-8"
LC_TIME="en_US.UTF-8"
LC_COLLATE="en_US.UTF-8"
LC_MONETARY="en_US.UTF-8"
LC_MESSAGES="en_US.UTF-8"
LC_PAPER="en_US.UTF-8"
LC_NAME="en_US.UTF-8"
LC_ADDRESS="en_US.UTF-8"
LC_TELEPHONE="en_US.UTF-8"
LC_MEASUREMENT="en_US.UTF-8"
LC_IDENTIFICATION="en_US.UTF-8"
LC_ALL=
--
/Björn
Add some more letters lower/upper and so on. Then compare sorting ex.
ö/z. Or look my some ex. 0/!/letter order with or without other chars.
insert into T_SORT values ( 10,'FINISH_Z');
insert into T_SORT values ( 11,'FINISH_a');
insert into T_SORT values ( 12,'FINISH_b');
insert into T_SORT values ( 13,'FINISH_A');
insert into T_SORT values ( 14,'FINISH_B');
insert into T_SORT values ( 15,'FINISH_ä');
insert into T_SORT values ( 16,'FINISH_Ä');
insert into T_SORT values ( 17,'FINISH_+');
insert into T_SORT values ( 18,'FINISH_@');
insert into T_SORT values ( 19,'FINISH_=');
insert into T_SORT values ( 20,'FINISH_]');
insert into T_SORT values ( 21,'FINISH_a0a');
insert into T_SORT values ( 22,'FINISH_a!a');
insert into T_SORT values ( 23,'FINISH_!');
insert into T_SORT values ( 24,'FINISH_012');
insert into T_SORT values ( 25,'FINISH_0aa');
insert into T_SORT values ( 26,'FINISH_!aa');
insert into T_SORT values ( 27,'FINISH_0');
insert into T_SORT values ( 28,'FINISH_!b!b');
insert into T_SORT values ( 29,'FINISH_a!b');
insert into T_SORT values ( 30,'FINISH_b!a');
insert into T_SORT values ( 31,'FINISH_!ab');
insert into T_SORT values ( 32,'FINISH_!b!a');
select * from T_SORT order by NAME ; -- use your db LC_COLLATE
-- using COLLATE = you have installed those locales in
-- your system, PG use those.
select * from T_SORT
ORDER BY name COLLATE "en_US" ;
select * from T_SORT
ORDER BY name COLLATE "fi_FI" ;
select * from T_SORT
ORDER BY name COLLATE "C" ; -- sorting weight = ascii value - simple
select * from T_SORT
ORDER BY name COLLATE "POSIX" ;
select * from T_SORT
ORDER BY name COLLATE "de_DE" ;
Sorting - it's not so easy ... but with COLLATE option you can "fix"
your order if you need / as you want - almost.
http://en.wikipedia.org/wiki/ISO_14651
http://en.wikipedia.org/wiki/European_ordering_rules
http://standards.iso.org/ittf/PubliclyAvailableStandards/index.html
- ISO/IEC 14651:2011/Amd 1:2012
https://www.debian.org/doc/manuals/intro-i18n/ - how the library works
http://en.wikipedia.org/wiki/Internationalization_and_localization
...
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/localeCompare
...
-jukka-
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