SQL> alter session set nls_language = english;


SQL> declare
  2      l_monday varchar2(255) default to_char( to_date( '20011231', 'yyyymmdd' ), 'day' );
  3      l_until  date;
  4  begin
  5      l_until := next_day( sysdate, l_monday );

  6      dbms_output.put_line( l_until  || ' ' || l_monday );
  7  end;
  8  /
14-JAN-02 monday

PL/SQL procedure successfully completed.


SQL> alter session set nls_language = french;

Session altered.

SQL> declare
  2      l_monday varchar2(255) default to_char( to_date( '20011231', 'yyyymmdd' ), 'day' );

  3      l_until  date;
  4  begin
  5      l_until := next_day( sysdate, l_monday );
  6      dbms_output.put_line( l_until  || ' ' || l_monday );
  7  end;
  8  /
14-JAN-02 lundi


PL/SQL procedure successfully completed.