The Oracle PL/SQL function NCHR returns character of NVARCHAR2 type corresponding to the input ASCII code, which is passed as parameter. Its output can be noted as the reverse of the ASCII function in Oracle.
The query below returns the character equivalent of ASCII code 65.
SQL> SELECT NCHR(65) FROM DUAL;
The query below shows the reverse path of ASCII code 65 using the ASCII function.
SQL> SELECT ASCII(NCHR(1)) FROM DUAL;