Is empty string and Null same?

Question

create table x
(empid number);
Table created.
insert into x values ('');
1 row created.
insert into x values (null);
1 row created.
SQL> set null <<>>
SQL> select * from x;
     EMPID
<<>>
<<>>So i can safely change an Insert statement like
insert into x values ('');to
insert into x values (null);Right?

Answer 1

michaels2 wrote:
char pads with spaces to the length of the data itemdon't think so - at least not on my 11.2.0.1.0Good. Oracle finally fixed it. Before 11.2 it was pretty much as ajallen noted:
Oracle Database 11g Enterprise Edition Release 11.1.0.6.0 - Production
PL/SQL Release 11.1.0.6.0 - Production
CORE    11.1.0.6.0      Production
TNS for 32-bit Windows: Version 11.1.0.6.0 - Production
NLSRTL Version 11.1.0.6.0 - Production
SET SERVEROUTPUT ON
DECLARE
    flag CHAR(2);
    PROCEDURE check_null (p_flag IN CHAR)
    IS
    BEGIN
      IF p_flag = '  '
        THEN
          dbms_output.put_line ('flag is equal to ''  ''');
        ELSIF p_flag IS NULL
          THEN
            dbms_output.put_line ('flag is null');
        ELSE
          dbms_output.put_line ('other');
      END IF;
    END;
BEGIN
    flag := '';
    check_null (flag);
    flag := NULL;
    check_null (flag);
END;
flag is equal to '  '
flag is null
PL/SQL procedure successfully completed.
alter session set events '10932 trace name context forever, level 16384';
DECLARE
    flag CHAR(2);
    PROCEDURE check_null (p_flag IN CHAR)
    IS
    BEGIN
      IF p_flag = '  '
        THEN
          dbms_output.put_line ('flag is equal to ''  ''');
        ELSIF p_flag IS NULL
          THEN
            dbms_output.put_line ('flag is null');
        ELSE
          dbms_output.put_line ('other');
      END IF;
    END;
BEGIN
    flag := '';
    check_null (flag);
    flag := NULL;
    check_null (flag);
END;
flag is null
flag is null
PL/SQL procedure successfully completed.
SQL>
Bug 727361: ZERO-LENGTH STRING DOES NOT RETURN NULL WHEN USED WITH CHAR DATA TYPE IN PL/SQL
SY.