IS_NUMBER - Equivalent SQL Query

The below query is used to check whether a varchar column contains only NUMBER or NON NUMBER data.

SELECT DECODE (REPLACE (TRANSLATE ('1123', '1234567890', '##########'), '#'),
               NULL, 'NUMBER','NON NUMER') RESULT
  FROM DUAL;

RESULT
------
NUMBER
1 row selected.

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SELECT DECODE (REPLACE (TRANSLATE ('11a23z', '1234567890', '##########'), '#'),
               NULL, 'NUMBER','NON NUMER') RESULT
  FROM DUAL;

RESULT 
---------
NON NUMER
1 row selected.