SQL - Check with regex if the string text is only composed of numbers

select
  text,
  case 
    when REGEXP_LIKE (trim(text), '^[0-9]*$') then 'Yes'
    else 'No'
  end "Only numbers ?"
from(
  select '19051989' text from dual
  union
  select '19 mai 1989' text from dual
);