Oracle PL/SQL/Char Functions/COMPOSE

compose("de" || unistr("\0300") )

   
SQL>
SQL>
SQL> select compose("de" || unistr("\0300") ) from dual;
dF
1 row selected.
SQL>

COMPOSE(x):Converts x to a Unicode string in its fully normalized form in the same character set as x

 

SQL> -- COMPOSE(x):Converts x to a Unicode string in its fully normalized form in the 
same character set as x. 
SQL>
SQL> select compose("o" || unistr("\0308") ) from dual;
C
-

SQL>
SQL> select compose("a" || unistr("\0302") ) from dual;
C
-

SQL> select compose("e" || unistr("\0301") ) from dual
  2
SQL>
SQL>