The following bug has been logged online:

Bug reference: 2554
Logged by: Jarosław Bojar
Email address: jarek.bojar (AT) gmail (DOT) com
PostgreSQL version: 8.1.4
Operating system: i386-redhat-linux-gnu, compiled by GCC
i386-redhat-linux-gcc (GCC) 4.1.0
Description: ILIKE operator works incorrectly
Details:

ILIKE operator works incorrectly with UTF8 encoding and Polish characters.
Consider following SQL statements:

CREATE DATABASE test ENCODING='UTF8';
\c test
CREATE TABLE the_table (val VARCHAR(50));
INSERT INTO the_table (val) VALUES ('Åšwiat');
INSERT INTO the_table (val) VALUES ('�ąka');
INSERT INTO the_table (val) VALUES ('Ćma');
INSERT INTO the_table (val) VALUES ('abc');
INSERT INTO the_table (val) VALUES ('ABC');

Without Polish characters ILIKE works correctly:
SELECT * FROM the_table WHERE val ilike 'abc';
val
-----
abc
ABC
(2 rows)

But with Polish characters it does not work correctly. Following queries
should give single row results, but they do not return any rows:

SELECT * FROM the_table WHERE val ilike 'świat';
val
-----
(0 rows)

SELECT * FROM the_table WHERE val ilike 'Å‚Ä…ka';
val
-----
(0 rows)

SELECT * FROM the_table WHERE val ilike 'ćma';
val
-----
(0 rows)

On the contrary functions like UPPER work correctly with Polish characters
and following queries produce correct results:

SELECT * FROM the_table WHERE UPPER(val) like UPPER('świat');
val
-------
Åšwiat
(1 row)

SELECT * FROM the_table WHERE UPPER(val) like UPPER('ćma');
val
-----
Ćma
(1 row)

SELECT * FROM the_table WHERE UPPER(val) like UPPER('Å‚Ä…ka');
val
------
�ąka
(1 row)

The bug is also present in PostgreSQL 8.1.0 on Windows XP.


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JarosÅaw Bojar wrote:
What does SHOW lc_collate say?

--
Peter Eisentraut
http://developer.postgresql.org/~petere/

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Peter Eisentraut <peter_e (AT) gmx (DOT) net> writes:
Even if the locale is set right, iwchareq() is completely broken
for multibyte charsets: it's trying to apply the system's tolower()
to a pg_wchar, which is highly unlikely to work. This has been a
known problem for awhile, but no one's stepped up to fix it.

regards, tom lane

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