The Oracle SOUNDEX function returns a phonetic representation (the way it sounds) of a string.

The SOUNDEX function is not case-sensitive. This means is that both uppercase and lowercase characters will generate the same SOUNDEX function return value.

SELECT SOUNDEX('dcodeman') Result FROM DUAL;

SELECT SOUNDEX('DCODEMAN') Result FROM DUAL;

SELECT SOUNDEX('decodeman') Result FROM DUAL;

SELECT SOUNDEX('DECODEMAN') Result FROM DUAL;