Função - Retorna apenas números

create or replace function retorna_apenas_numero(xvalor in varchar) return varchar2 deterministic is

begin

  return trim(replace(translate(xvalor,'.-/!@#$%¨&*<>{}[]=+()\+abcdefghijklmnopqrstuvxzwyABCDEFGHIJKLMNOPQRSTUVXZWYáçéíóúàâêôãõüÁÇÉÍÓÚÀÂÊÔÃÕÜ;:  ',' '),' ',''));

end;

select retorna_apenas_numero('1 a 2 b 3 c') from dual

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