Oracle SQL testar quando a coluna possui number ou varchar

SELECT case when trim(TRANSLATE('valor a ser testado', '0123456789-,.', ' ')) is null
then 'numeric'
else 'alpha'
end
FROM dual;

SELECT case when regexp_like('99', '^\d+(\.\d+)?$')
then 'numeric'
else 'alfa'
end
FROM  dual;


SELECT case when trim(TRANSLATE('0', '0123456789-,.', ' ')) is null
            then 'numeric'
            else 'alpha'
       end test_it
FROM dual;