Description: Returns char with all of its single-byte characters converted to their corresponding multibyte characters. char can be of datatype CHAR, VARCHAR2, NCHAR, or NVARCHAR2. The value returned is in the same datatype as char.
Any single-byte characters in char that have no multibyte equivalents appear in the output string as single-byte characters. This function is useful only if your database character set contains both single-byte and multibyte characters.
This function does not support CLOB data directly. However, CLOBs can be passed in as arguments through implicit data conversion.