BigQuery: Convert accented characters to their plain ascii equivalents

I have the following string:

brasília

And I need to convert to:

brasilia

Withou the ´ accent!

How can I do on BigQuery?

Thank you!

Try below as quick and simple option for you:

#standardSQL
WITH lookups AS (
  SELECT 
  'ç,æ,œ,á,é,í,ó,ú,à,è,ì,ò,ù,ä,ë,ï,ö,ü,ÿ,â,ê,î,ô,û,å,ø,Ø,Å,Á,À,Â,Ä,È,É,Ê,Ë,Í,Î,Ï,Ì,Ò,Ó,Ô,Ö,Ú,Ù,Û,Ü,Ÿ,Ç,Æ,Œ,ñ' AS accents,
  'c,ae,oe,a,e,i,o,u,a,e,i,o,u,a,e,i,o,u,y,a,e,i,o,u,a,o,O,A,A,A,A,A,E,E,E,E,I,I,I,I,O,O,O,O,U,U,U,U,Y,C,AE,OE,n' AS latins
),
pairs AS (
  SELECT accent, latin FROM lookups, 
    UNNEST(SPLIT(accents)) AS accent WITH OFFSET AS p1, 
    UNNEST(SPLIT(latins)) AS latin WITH OFFSET AS p2
  WHERE p1 = p2
),
yourTableWithWords AS (
  SELECT word FROM UNNEST(
        SPLIT('brasília,ångström,aperçu,barège, beau idéal, belle époque, béguin, bête noire, bêtise, Bichon Frisé, blasé, blessèd, bobèche, boîte, bombé, Bön, Boötes, boutonnière, bric-à-brac, Brontë Beyoncé,El Niño')
    ) AS word
)
SELECT 
  word AS word_with_accent, 
  (SELECT STRING_AGG(IFNULL(latin, char), '')
    FROM UNNEST(SPLIT(word, '')) char
    LEFT JOIN pairs
    ON char = accent) AS word_without_accent
FROM yourTableWithWords   

Output is

word_with_accent word_without_accent     
blessèd         blessed  
El Niño         El Nino  
belle époque    belle epoque     
boîte           boite    
Boötes          Bootes   
blasé           blase    
ångström        angstrom     
bobèche         bobeche  
barège          barege   
bric-à-brac     bric-a-brac  
bête noire      bete noire   
Bichon Frisé    Bichon Frise     
Brontë Beyoncé  Bronte Beyonce   
bêtise          betise   
beau idéal      beau ideal   
bombé           bombe    
brasília        brasilia     
boutonnière     boutonniere  
aperçu          apercu   
béguin          beguin   
Bön             Bon   

UPDATE

Below is how to pack this logic into SQL UDF - so accent2latin(word) can be called to make a "magic"

#standardSQL
CREATE TEMP FUNCTION accent2latin(word STRING) AS
((
  WITH lookups AS (
    SELECT 
    'ç,æ,œ,á,é,í,ó,ú,à,è,ì,ò,ù,ä,ë,ï,ö,ü,ÿ,â,ê,î,ô,û,å,ø,Ø,Å,Á,À,Â,Ä,È,É,Ê,Ë,Í,Î,Ï,Ì,Ò,Ó,Ô,Ö,Ú,Ù,Û,Ü,Ÿ,Ç,Æ,Œ,ñ' AS accents,
    'c,ae,oe,a,e,i,o,u,a,e,i,o,u,a,e,i,o,u,y,a,e,i,o,u,a,o,O,A,A,A,A,A,E,E,E,E,I,I,I,I,O,O,O,O,U,U,U,U,Y,C,AE,OE,n' AS latins
  ),
  pairs AS (
    SELECT accent, latin FROM lookups, 
      UNNEST(SPLIT(accents)) AS accent WITH OFFSET AS p1, 
      UNNEST(SPLIT(latins)) AS latin WITH OFFSET AS p2
    WHERE p1 = p2
  )
  SELECT STRING_AGG(IFNULL(latin, char), '')
  FROM UNNEST(SPLIT(word, '')) char
  LEFT JOIN pairs
  ON char = accent
));

WITH yourTableWithWords AS (
  SELECT word FROM UNNEST(
        SPLIT('brasília,ångström,aperçu,barège, beau idéal, belle époque, béguin, bête noire, bêtise, Bichon Frisé, blasé, blessèd, bobèche, boîte, bombé, Bön, Boötes, boutonnière, bric-à-brac, Brontë Beyoncé,El Niño')
    ) AS word
)
SELECT 
  word AS word_with_accent, 
  accent2latin(word) AS word_without_accent
FROM yourTableWithWords