Problem with Polish special characters in WHERE clause

Database

Problem with Polish special characters in WHERE clause

Hi All,

I have the following problem with Polish special characters.

I've got 2 tables:


CREATE MULTISET TABLE D_DB_STAGE.TEST_latin
(
COL1 VARCHAR(10) CHARACTER SET LATIN NOT CASESPECIFIC
) PRIMARY INDEX (COL1);

CREATE MULTISET TABLE D_DB_STAGE.TEST_unicode
(
COL1 VARCHAR(10) CHARACTER SET UNICODE NOT CASESPECIFIC
) PRIMARY INDEX (COL1);

In the first table named TEST_latin column COL1 has LATIN character set.

In the second table named TEST_unicode column COL1 has UNICODE character set.

I insert now the same data into those 2 tables:


INSERT INTO D_DB_STAGE.TEST_latin (COL1) VALUES('Ł123');
INSERT INTO D_DB_STAGE.TEST_latin (COL1) VALUES('ł123');
INSERT INTO D_DB_STAGE.TEST_latin (COL1) VALUES('Ś123');
INSERT INTO D_DB_STAGE.TEST_latin (COL1) VALUES('ś123');
INSERT INTO D_DB_STAGE.TEST_latin (COL1) VALUES('Ó123');
INSERT INTO D_DB_STAGE.TEST_latin (COL1) VALUES('ó123');
INSERT INTO D_DB_STAGE.TEST_latin (COL1) VALUES('Ę123');
INSERT INTO D_DB_STAGE.TEST_latin (COL1) VALUES('ę123');
INSERT INTO D_DB_STAGE.TEST_latin (COL1) VALUES('Ą123');
INSERT INTO D_DB_STAGE.TEST_latin (COL1) VALUES('ą123');
INSERT INTO D_DB_STAGE.TEST_latin (COL1) VALUES('Ń123');
INSERT INTO D_DB_STAGE.TEST_latin (COL1) VALUES('ń123');
INSERT INTO D_DB_STAGE.TEST_latin (COL1) VALUES('Ż123');
INSERT INTO D_DB_STAGE.TEST_latin (COL1) VALUES('ż123');
INSERT INTO D_DB_STAGE.TEST_latin (COL1) VALUES('Ź123');
INSERT INTO D_DB_STAGE.TEST_latin (COL1) VALUES('ź123');
INSERT INTO D_DB_STAGE.TEST_latin (COL1) VALUES('Ć123');
INSERT INTO D_DB_STAGE.TEST_latin (COL1) VALUES('ć123');

INSERT INTO D_DB_STAGE.TEST_unicode (COL1) VALUES('Ł123');
INSERT INTO D_DB_STAGE.TEST_unicode (COL1) VALUES('ł123');
INSERT INTO D_DB_STAGE.TEST_unicode (COL1) VALUES('Ś123');
INSERT INTO D_DB_STAGE.TEST_unicode (COL1) VALUES('ś123');
INSERT INTO D_DB_STAGE.TEST_unicode (COL1) VALUES('Ó123');
INSERT INTO D_DB_STAGE.TEST_unicode (COL1) VALUES('ó123');
INSERT INTO D_DB_STAGE.TEST_unicode (COL1) VALUES('Ę123');
INSERT INTO D_DB_STAGE.TEST_unicode (COL1) VALUES('ę123');
INSERT INTO D_DB_STAGE.TEST_unicode (COL1) VALUES('Ą123');
INSERT INTO D_DB_STAGE.TEST_unicode (COL1) VALUES('ą123');
INSERT INTO D_DB_STAGE.TEST_unicode (COL1) VALUES('Ń123');
INSERT INTO D_DB_STAGE.TEST_unicode (COL1) VALUES('ń123');
INSERT INTO D_DB_STAGE.TEST_unicode (COL1) VALUES('Ż123');
INSERT INTO D_DB_STAGE.TEST_unicode (COL1) VALUES('ż123');
INSERT INTO D_DB_STAGE.TEST_unicode (COL1) VALUES('Ź123');
INSERT INTO D_DB_STAGE.TEST_unicode (COL1) VALUES('ź123');
INSERT INTO D_DB_STAGE.TEST_unicode (COL1) VALUES('Ć123');
INSERT INTO D_DB_STAGE.TEST_unicode (COL1) VALUES('ć123');

And I select the data from both tables using the same SQL statement:


SELECT 'Test Ł', COL1 FROM D_DB_STAGE.TEST_latin WHERE COL1 LIKE 'Ł%' UNION ALL
SELECT 'Test ł', COL1 FROM D_DB_STAGE.TEST_latin WHERE COL1 LIKE 'ł%' UNION ALL
SELECT 'Test Ś', COL1 FROM D_DB_STAGE.TEST_latin WHERE COL1 LIKE 'Ś%' UNION ALL
SELECT 'Test ś', COL1 FROM D_DB_STAGE.TEST_latin WHERE COL1 LIKE 'ś%' UNION ALL
SELECT 'Test Ó', COL1 FROM D_DB_STAGE.TEST_latin WHERE COL1 LIKE 'Ó%' UNION ALL
SELECT 'Test ó', COL1 FROM D_DB_STAGE.TEST_latin WHERE COL1 LIKE 'ó%' UNION ALL
SELECT 'Test Ę', COL1 FROM D_DB_STAGE.TEST_latin WHERE COL1 LIKE 'Ę%' UNION ALL
SELECT 'Test ę', COL1 FROM D_DB_STAGE.TEST_latin WHERE COL1 LIKE 'ę%' UNION ALL
SELECT 'Test Ą', COL1 FROM D_DB_STAGE.TEST_latin WHERE COL1 LIKE 'Ą%' UNION ALL
SELECT 'Test ą', COL1 FROM D_DB_STAGE.TEST_latin WHERE COL1 LIKE 'ą%' UNION ALL
SELECT 'Test Ń', COL1 FROM D_DB_STAGE.TEST_latin WHERE COL1 LIKE 'Ń%' UNION ALL
SELECT 'Test ń', COL1 FROM D_DB_STAGE.TEST_latin WHERE COL1 LIKE 'ń%' UNION ALL
SELECT 'Test Ż', COL1 FROM D_DB_STAGE.TEST_latin WHERE COL1 LIKE 'Ż%' UNION ALL
SELECT 'Test ż', COL1 FROM D_DB_STAGE.TEST_latin WHERE COL1 LIKE 'ż%' UNION ALL
SELECT 'Test Ź', COL1 FROM D_DB_STAGE.TEST_latin WHERE COL1 LIKE 'Ź%' UNION ALL
SELECT 'Test ź', COL1 FROM D_DB_STAGE.TEST_latin WHERE COL1 LIKE 'ź%' UNION ALL
SELECT 'Test Ć', COL1 FROM D_DB_STAGE.TEST_latin WHERE COL1 LIKE 'Ć%' UNION ALL
SELECT 'Test ć', COL1 FROM D_DB_STAGE.TEST_latin WHERE COL1 LIKE 'ć%';

SELECT 'Test Ł', COL1 FROM D_DB_STAGE.TEST_unicode WHERE COL1 LIKE 'Ł%' UNION ALL
SELECT 'Test ł', COL1 FROM D_DB_STAGE.TEST_unicode WHERE COL1 LIKE 'ł%' UNION ALL
SELECT 'Test Ś', COL1 FROM D_DB_STAGE.TEST_unicode WHERE COL1 LIKE 'Ś%' UNION ALL
SELECT 'Test ś', COL1 FROM D_DB_STAGE.TEST_unicode WHERE COL1 LIKE 'ś%' UNION ALL
SELECT 'Test Ó', COL1 FROM D_DB_STAGE.TEST_unicode WHERE COL1 LIKE 'Ó%' UNION ALL
SELECT 'Test ó', COL1 FROM D_DB_STAGE.TEST_unicode WHERE COL1 LIKE 'ó%' UNION ALL
SELECT 'Test Ę', COL1 FROM D_DB_STAGE.TEST_unicode WHERE COL1 LIKE 'Ę%' UNION ALL
SELECT 'Test ę', COL1 FROM D_DB_STAGE.TEST_unicode WHERE COL1 LIKE 'ę%' UNION ALL
SELECT 'Test Ą', COL1 FROM D_DB_STAGE.TEST_unicode WHERE COL1 LIKE 'Ą%' UNION ALL
SELECT 'Test ą', COL1 FROM D_DB_STAGE.TEST_unicode WHERE COL1 LIKE 'ą%' UNION ALL
SELECT 'Test Ń', COL1 FROM D_DB_STAGE.TEST_unicode WHERE COL1 LIKE 'Ń%' UNION ALL
SELECT 'Test ń', COL1 FROM D_DB_STAGE.TEST_unicode WHERE COL1 LIKE 'ń%' UNION ALL
SELECT 'Test Ż', COL1 FROM D_DB_STAGE.TEST_unicode WHERE COL1 LIKE 'Ż%' UNION ALL
SELECT 'Test ż', COL1 FROM D_DB_STAGE.TEST_unicode WHERE COL1 LIKE 'ż%' UNION ALL
SELECT 'Test Ź', COL1 FROM D_DB_STAGE.TEST_unicode WHERE COL1 LIKE 'Ź%' UNION ALL
SELECT 'Test ź', COL1 FROM D_DB_STAGE.TEST_unicode WHERE COL1 LIKE 'ź%' UNION ALL
SELECT 'Test Ć', COL1 FROM D_DB_STAGE.TEST_unicode WHERE COL1 LIKE 'Ć%' UNION ALL
SELECT 'Test ć', COL1 FROM D_DB_STAGE.TEST_unicode WHERE COL1 LIKE 'ć%';

The results from both queries are the same:







  'Test' COL1
1 Test ą ą123
2 Test Ą Ą123
3 Test Ć ć123
4 Test ć ć123
5 Test Ć Ć123
6 Test ć Ć123
7 Test Ę ę123
8 Test ę ę123
9 Test Ę Ę123
10 Test ę Ę123
11 Test ł ł123
12 Test Ł Ł123
13 Test Ń ń123
14 Test ń ń123
15 Test Ń Ń123
16 Test ń Ń123
17 Test Ó ó123
18 Test ó ó123
19 Test ó Ó123
20 Test Ó Ó123
21 Test ś ś123
22 Test Ś Ś123
23 Test ź ź123
24 Test Ź Ź123
25 Test ż ż123
26 Test Ż Ż123

The Question is:

Why only letters ć, Ć, ę, Ę, ń, Ń, ó and Ó where selected as I expected? I mean, the query searching for letter "ć" returned the small "ć" and the big "Ć" as well.

Why the letters ą, Ą, ł, Ł, ś, Ś, ż, Ż, ź and Ź where not selected in the same way like letters above? I mean, the query searching for letter "ł" returned only the small "ł" and the query searching for letter "Ł" returned only the big "Ł".

The SQL:

SELECT 'Test ć', COL1 FROM D_DB_STAGE.TEST_unicode WHERE COL1 LIKE 'ć%';

Returned the record with ć123 as well as the record with Ć123.

But the SQL:

SELECT 'Test ł', COL1 FROM D_DB_STAGE.TEST_unicode WHERE COL1 LIKE 'ł%';

Returned the record only with ł123. I was expecting to see the record with Ł123 as well.

And the same is with the query below:

SELECT 'Test Ł', COL1 FROM D_DB_STAGE.TEST_unicode WHERE COL1 LIKE 'Ł%';

It returned only Ł123. It doesn't show me the record with ł123.

Are the letters "ł" and "Ł" treated as a completely different letters by Teradata?

Why Teradata doesn't know that the letters "ł" and "Ł" are actualy the same letters?

As you can see, using the character set LATIN or UNICODE doesn't change the result set at all.

Thanks in advance.

Regards.

6 REPLIES
Junior Contributor

Re: Problem with Polish special characters in WHERE clause

How did you insert those polish characters into a LATIN column?

Most eastern european diacritical characters are not included in Teradata's LATIN.

Regarding your result, works fine for me, all rows are returned as expected from TEST_unicode.

What's your TD release and your client character set?

Teradata Employee

Re: Problem with Polish special characters in WHERE clause

The col1 column is defined as 'not casespecific'. It appears as if you want a casespecific comparison. If so, define this attribute at the column level or in the query.

re:Why the letters ą, Ą, ł, Ł, ś, Ś, ż, Ż, ź and Ź where not selected in the same way like letters above?

These characters are in the Latin Extended-A script of the Unicode server character set. They are not supported in the Latin server character set. Since your insert did not fail, they were probably converted to the 0x1A error character in Latin.

What client character set are you using? Try using UTF8 with the Unicode server character set. 

Refer to the International Character Set Support reference for details.

-Dave

Re: Problem with Polish special characters in WHERE clause

dnoeth,

All the CHAR and VARCHAR columns at this customer have LATIN character set.

I inserted Polish characters into a LATIN column because the session character set was ASCII.

When you change the session character set to UTF8 you can't insert those rows into LATIN column.

But with UTF8 session character set everything works fine in case of UNICODE column. Probably you have UTF8 as well that's why everything was OK for you.

Re: Problem with Polish special characters in WHERE clause

david,

Thanks for the explanation.

I'm using ASCII client character set and when I changed to UTF8 everything started to work OK with UNICODE column character set.

Junior Contributor

Re: Problem with Polish special characters in WHERE clause

LATIN can't store polish characters, you must use UNICODE and use UTF8 or UTF16 sessions.

After inserting those polish characters in an ASCII session you should select them. You'll notice that most of them are no more diacritical characters, accents were simply stripped off.

Teradata Employee

Re: Problem with Polish special characters in WHERE clause

The Teradata ASCII client character set does not support Polish characters either. ASCII to the LATIN server character set is a passthrough translation which does not change any byte values. Because of this property, it is often misused to avoid the detection of conversion errors but this can lead to problems with uppercasing, collation, etc.

So as Deiter said, the best practice is Unicode. Note that Latin1250_1A0 is also available as a single-byte character set alternative to ASCII.