Guys, I was able to solve it using the following:
SELECT
LENGTH(TRIM(TRANSLATE(TABELA.MEU_CAMPO_A_TESTAR, '0123456789',' '))) TESTE
FROM DUAL;
If the TEST returns null, the field contains only numbers.
With this I made the following CASE to fetch information from one or another column according to the test.
CASE WHEN ( LENGTH(TRIM(TRANSLATE(TABELA.MEU_CAMPO_A_TESTAR, '0123456789',' '))) IS NULL ) THEN TABELA.CAMPO_CASO_NUMERICO ELSE TABELA.MEU_CAMPO_A_TESTAR END AS CAMPO_APRESENTADO
That’s how I solved my problem.
I hope it will help those who seek a similar solution.