The underlying database datatype for this example is Unicode UTF-8 : Unicode « PL SQL Data Types « Oracle PL/SQL Tutorial

1. Oracle PL/SQL Tutorial
2. PL SQL Data Types
3. Unicode

SQL> DECLARE
  2
  3     x CHAR(30 CHAR) := 'The character ?is two-bytes.';
  4  BEGIN
  5     --Find the location of "is" in terms of characters
  6     DBMS_OUTPUT.PUT_LINE(INSTR(x,'is'));
  7
  8     --Find the location of "is" in terms of bytes
  9     DBMS_OUTPUT.PUT_LINE(INSTRB(x,'is'));
 10  END;
 11  /

PL/SQL procedure successfully completed.

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