remove special characters from query without using the replace function - oracle

Question

I have some foreign language names in my query. The problem is, I don't know where all the special characters are, so using the REPLACE function will not be helpful because there are over 500,000 rows. Some foreign names appear like this for example:
I want the name to appear like this instead "COLLEGE BOREAL DARTS APPLIQUES ET DE TECHNOLOGIE"
Is there a way to achieve this without using the replace function? So that it works on other Names on the list as well
I tried something like this that I saw in another post:
SELECT
CTE.COLLEGE_NAME COLLATE Cyrillic_General_CI_AI
FROM SCHOOLS cte
But it did not work. If someone could please help me solve this, that would be great! thank you

Answer 1

You seem to be talking about both accented and special characters. As #Sayan showed you can use nlssort to remove the accents, but as well as having to deal with the case change, it doesn't remove things like the trademark symbol (which you mentioned0 as you might expect or want - the '™' is converted to 'tm' which is clever but unhelpful here, and it throws out the translate too (as shown here, adding examples to Sayan's code).
Another approach that might work for you is to use convert (which Oracle recommend not to do) or utl_raw/utl_i18n functions to convert your values to plain ASCII, which takes care of the accents (hopefully all of them; I haven't tested extensively, and the discussion #Littlefoot linked to shows a lot of variations), and replaces any other non-ASCII values with a ?, which you can then conventiently remove along with other punctuation and symbols:
select college_name,
regexp_replace(
utl_i18n.raw_to_char(utl_i18n.string_to_raw(college_name, 'US7ASCII'), 'US7ASCII'),
'[[:punct:]]',
null) as result
from schools
which with your example and another with a trademark symbol gives:
COLLEGE_NAME
RESULT
COLLÈGE BORÉAL D’ARTS APPLIQUÉS ET DE TECHNOLOGIE
COLLEGE BOREAL DARTS APPLIQUES ET DE TECHNOLOGIE
Collectives™ on Stack Overflow
Collectives on Stack Overflow
db<>fiddle including some variations; but don't use the convert ones *8-)

Answer 2

Of course, you can remove ascent/umlauts from characters.
First of all, look at this example:
with t(n,name) as (
select 1, 'Löwenbrauerei' from dual union all
select 2, 'LÖwenbrauerei' from dual union all
select 3, 'Lowenbrauerei' from dual union all
select 4, 'LOwenbrauerei' from dual
)
select
n
,name
,utl_raw.cast_to_varchar2(nlssort(name, 'NLS_SORT=BINARY_AI')) name_AI
from t;
Results:
N NAME NAME_AI
---------- -------------- --------------------
1 Löwenbrauerei lowenbrauerei
2 LÖwenbrauerei lowenbrauerei
3 Lowenbrauerei lowenbrauerei
4 LOwenbrauerei lowenbrauerei
As you can see NLSSORT(..., 'NLS_SORT=BINARY_AI') removes all ascents and changes all to lower-case characters, so you just need to restore original upper/lower-case characters. For example you can use it with translate:
with t(n,name) as (
select 1, 'Löwenbrauerei' from dual union all
select 2, 'LÖwenbrauerei' from dual union all
select 3, 'Lowenbrauerei' from dual union all
select 4, 'LOwenbrauerei' from dual
)
select
n
,name
,upper(name)
,lower(utl_raw.cast_to_varchar2(nlssort(name, 'NLS_SORT=BINARY_AI'))) name_AI_lower
,upper(utl_raw.cast_to_varchar2(nlssort(name, 'NLS_SORT=BINARY_AI'))) name_AI_upper
,translate(
translate(
name
,upper(name)
,upper(utl_raw.cast_to_varchar2(nlssort(name, 'NLS_SORT=BINARY_AI')))
)
,lower(name)
,utl_raw.cast_to_varchar2(nlssort(name, 'NLS_SORT=BINARY_AI'))
) as name_ascent_removed
from t;
Results:
N NAME UPPER(NAME) NAME_AI_LOWER NAME_AI_UPPER NAME_ASCENT_REMOVED
---------- -------------- -------------- -------------------- -------------------- --------------------------------------------------------
1 Löwenbrauerei LÖWENBRAUEREI lowenbrauerei LOWENBRAUEREI Lowenbrauerei
2 LÖwenbrauerei LÖWENBRAUEREI lowenbrauerei LOWENBRAUEREI LOwenbrauerei
3 Lowenbrauerei LOWENBRAUEREI lowenbrauerei LOWENBRAUEREI Lowenbrauerei
4 LOwenbrauerei LOWENBRAUEREI lowenbrauerei LOWENBRAUEREI LOwenbrauerei
ps. probably you can just to set codepage/font on the client that ignores them...