Is this a bug in sqlite? - sql

I have following query for Czech language:
select Id,Name
from Account
where Name like '%Še%'
it will return me correct result. But if I change Š to š in my query:
select Id,Name
from Account
where Name like '%še%'
It returns nothing. Is this a sqlite bug?

https://www.sqlite.org/lang_expr.html#like:
Important Note: SQLite only understands upper/lower case for ASCII characters by default. The LIKE operator is case sensitive by default for unicode characters that are beyond the ASCII range. For example, the expression 'a' LIKE 'A' is TRUE but 'æ' LIKE 'Æ' is FALSE. The ICU extension to SQLite includes an enhanced version of the LIKE operator that does case folding across all unicode characters.
So the solution to your problem would be to get an SQLite version with the ICU extension.

Related

SQL Special Characters on Tables

we are using following SQL to identify several rows which contain only SPECIAL CHARACTERs 'F#C(!!'. But seems it's not capturing some SPECIAL CHARACTER like 'F#C(!!'. Script should capture only special characters. Could you please share the optimized script to use for this scenario case
when regexp_like(column_name '^[^a-zA-Z]*$') then 'number'
when regexp_like(column_name, '^[^g-zG-Z]*$') then 'hex'
else 'string'
end
Try removing the ^ and $ anchors from the regex pattern you are using with regexp_like:
select *
from your_table
where regexp_like(column_name, '[^a-zA-Z]');
The above logic would check for the presence of one or more characters which are not letters. If you instead want to check for non alphanumeric, then use [^A-Za-z0-9].

Remove accents from string in Oracle

When trying to remove all accents from a string in Oracle using the techniques described in this stackoverflow answer: how replace accented letter in a varchar2 column in oracle I’m getting mixed results.
select CONVERT('JUAN ROMÄN', 'US7ASCII') from dual;
Returns the original string but replaces characters with for example ñ by a question mark (probably because of the chosen charset - tests with different charsets led to different results).
Using the following technique:
select utl_raw.cast_to_varchar2(nlssort(NAME_USER, 'nls_sort=binary_ai')) from YOUR_TABLE;
Returns the complete string but also places a NUL value at the end of the string.
Is there a characterset that I can use with Spanish accents to get a correct result (the original string with the different accents removed); is there a way to avoid the NUL value in the utl_raw.cast_to_varchar2 technique?
Based on the comments the the replace char(0) seems to remove the NUL value. For example
select
upper(utl_raw.cast_to_varchar2((nlssort('this is áà ñew test','nls_sort=binary_ai')))) as test,
replace(upper(utl_raw.cast_to_varchar2((nlssort('this is áà ñew test','nls_sort=binary_ai')))),chr(0),'') as test2
from dual;
If possible I would however to have a more 'straightforward/simpler' solution.
You can use TRANSLATE(your_string, from_chars, to_chars) https://docs.oracle.com/cd/B19306_01/server.102/b14200/functions196.htm
Just put all chars with accents in from_chars string and their corresponding replacement chars in to_chars.

Accent-Insensitive Alphabetization and Searching [duplicate]

I am new in Android and I'm working on a query in SQLite.
My problem is that when I use accent in strings e.g.
ÁÁÁ
ááá
ÀÀÀ
ààà
aaa
AAA
If I do:
SELECT * FROM TB_MOVIE WHERE MOVIE_NAME LIKE '%a%' ORDER BY MOVIE_NAME;
It's return:
AAA
aaa (It's ignoring the others)
But if I do:
SELECT * FROM TB_MOVIE WHERE MOVIE_NAME LIKE '%à%' ORDER BY MOVIE_NAME;
It's return:
ààà (ignoring the title "ÀÀÀ")
I want to select strings in a SQLite DB without caring for the accents and the case. Please help.
Generally, string comparisons in SQL are controlled by column or expression COLLATE rules. In Android, only three collation sequences are pre-defined: BINARY (default), LOCALIZED and UNICODE. None of them is ideal for your use case, and the C API for installing new collation functions is unfortunately not exposed in the Java API.
To work around this:
Add another column to your table, for example MOVIE_NAME_ASCII
Store values into this column with the accent marks removed. You can remove accents by normalizing your strings to Unicode Normal Form D (NFD) and removing non-ASCII code points since NFD represents accented characters roughly as plain ASCII + combining accent markers:
String asciiName = Normalizer.normalize(unicodeName, Normalizer.Form.NFD)
.replaceAll("[^\\p{ASCII}]", "");
Do your text searches on this ASCII-normalized column but display data from the original unicode column.
In Android sqlite, LIKE and GLOB ignore both COLLATE LOCALIZED and COLLATE UNICODE (they only work for ORDER BY). However, there is a solution without having to add extra columns to your table. As #asat explains in this answer, you can use GLOB with a pattern that will replace each letter with all the available alternatives of that letter. In Java:
public static String addTildeOptions(String searchText) {
return searchText.toLowerCase()
.replaceAll("[aáàäâã]", "\\[aáàäâã\\]")
.replaceAll("[eéèëê]", "\\[eéèëê\\]")
.replaceAll("[iíìî]", "\\[iíìî\\]")
.replaceAll("[oóòöôõ]", "\\[oóòöôõ\\]")
.replaceAll("[uúùüû]", "\\[uúùüû\\]")
.replace("*", "[*]")
.replace("?", "[?]");
}
And then (not literally like this, of course):
SELECT * from table WHERE lower(column) GLOB "*addTildeOptions(searchText)*"
This way, for example in Spanish, a user searching for either mas or más will get the search converted into m[aáàäâã]s, returning both results.
It is important to notice that GLOB ignores COLLATE NOCASE, that's why I converted everything to lower case both in the function and in the query. Notice also that the lower() function in sqlite doesn't work on non-ASCII characters - but again those are probably the ones that you are already replacing!
The function also replaces both GLOB wildcards, * and ?, with "escaped" versions.
You can use Android NDK to recompile the SQLite source including the desired ICU (International Components for Unicode).
Explained in russian here:
http://habrahabr.ru/post/122408/
The process of compiling the SQLilte with source with ICU explained here:
How to compile sqlite with ICU?
Unfortunately you will end up with different APKs for different CPUs.
You need to look at these, not as accented characters, but as entirely different characters. You might as well be looking for a, b, or c. That being said, I would try using a regex for it. It would look something like:
SELECT * from TB_MOVIE WHERE MOVIE_NAME REGEXP '.*[aAàÀ].*' ORDER BY MOVIE_NAME;

Removing replacement character � from column

Based on my research so far this character indicates bad encoding between the database and front end. Unfortunately, I don't have any control over either of those. I'm using Teradata Studio.
How can I filter this character out? I'm trying to perform a REGEX_SUBSTR function on a column that occasionally contains �, which throws the error "The string contains an untranslatable character".
Here is my SQL. AIRCFT_POSITN_ID is the column that contains the replacement character.
SELECT DISTINCT AIRCFT_POSITN_ID,
REGEXP_SUBSTR(AIRCFT_POSITN_ID, '[0-9]+') AS AUTOROW
FROM PROD_MAE_MNTNC_VW.FMR_DISCRPNCY_DFRL
WHERE DFRL_CREATE_TMS > CURRENT_DATE -25
Your diagnostic is correct, so first of all, you might want to check the Session Character Set (it is part of the connection definition).
If it is ASCII change it to UTF8 and you will be able to see the original characters instead of the substitute character.
And in case the character is indeed part of the data and not just an indication for encoding translations issues:
The substitute character AKA SUB (DEC: 26 HEX: 1A) is quite unique in Teradata.
you cannot use it directly -
select '�';
-- [6706] The string contains an untranslatable character.
select '1A'XC;
-- [6706] The string contains an untranslatable character.
If you are using version 14.0 or above you can generate it with the CHR function:
select chr(26);
If you're below version 14.0 you can generate it like this:
select translate (_unicode '05D0'XC using unicode_to_latin with error);
Once you have generated the character you can now use it with REPLACE or OTRANSLATE
create multiset table t (i int,txt varchar(100) character set latin) unique primary index (i);
insert into t (i,txt) values (1,translate ('Hello שלום world עולם' using unicode_to_latin with error));
select * from t;
-- Hello ���� world ����
select otranslate (txt,chr(26),'') from t;
-- Hello world
select otranslate (txt,translate (_unicode '05D0'XC using unicode_to_latin with error),'') from t;
-- Hello world
BTW, there are 2 versions for OTRANSLATE and OREPLACE:
The functions under syslib works with LATIN.
the functions under TD_SYSFNLIB works with UNICODE.
In addition to Dudu's excellent answer above, I wanted to add the following now that I've encountered the issue again and had more time to experiment. The following SELECT command produced an untranslatable character:
SELECT IDENTIFY FROM PROD_MAE_MNTNC_VW.SCHD_MNTNC;
IDENTIFY
24FEB1747659193DC330A163DCL�ORD
Trying to perform a REGEXP_REPLACE or OREPLACE directly on this character produces an error:
Failed [6706 : HY000] The string contains an untranslatable character.
I changed the CHARSET property in my Teradata connection from UTF8 to ASCII and I could now see the offending character, looks like a tab
IDENTIFY
Using the TRANSLATE_CHK command using this specific conversion succeeds and identifies the position of the offending character (Note that this does not work using the UTF8 charset):
TRANSLATE_CHK(IDENTIFY USING KANJI1_SBC_TO_UNICODE) AS BADCHAR
BADCHAR
28
Now this character can be dealt with using some CASE statements to remove the bad character and retain the remainder of the string:
CASE WHEN TRANSLATE_CHK(IDENTIFY USING KANJI1_SBC_TO_UNICODE) = 0 THEN IDENTIFY
ELSE SUBSTR(IDENTIFY, 1, TRANSLATE_CHK(IDENTIFY USING KANJI1_SBC_TO_UNICODE)-1)
END AS IDENTIFY
Hopes this helps someone out.

howto cut text from specific character in sqlite query

SQLITE Query question:
I have a query which returns string with the character '#' in it.
I would like to remove all characters after this specific character '#':
select field from mytable;
result :
text#othertext
text2#othertext
text3#othertext
So in my sample I would like to create a query which only returns :
text
text2
text3
I tried something with instr() to get the index, but instr() was not recognized as a function -> SQL Error: no such function: instr (probably old version of db . sqlite_version()-> 3.7.5).
Any hints howto achieve this ?
There are two approaches:
You can rtrim the string of all characters other than the # character.
This assumes, of course, that (a) there is only one # in the string; and (b) that you're dealing with simple strings (e.g. 7-bit ASCII) in which it is easy to list all the characters to be stripped.
You can use sqlite3_create_function to create your own rendition of INSTR. The specifics here will vary a bit upon how you're using