TO_SINGLE_BYTE is one of the vital Conversion functions of Oracle. It is used to convert a character value with all of the multi-byte characters to single-byte characters. The TO_SINGLE_BYTE function is supported in the various versions of the Oracle/PLSQL, including, Oracle 12c, Oracle 11g, Oracle 10g, Oracle 9i and Oracle 8i.
TO_SINGLE_BYTE ( char )
char: It is used to specify the character value to be converted.
select TO_SINGLE_BYTE( 'Hello World' ) from dual;
Here, the result will be a single-byte character value.