Having problem with join

[stecal]

Note the order of the where clause tables:

SQL> select * from xxx;

        ID LOCATION
---------- ----------
         1 AAAA
         2 BBB
         3 BBBB
         4 DDDD

SQL> select * from yyy;

        ID LOCATION
---------- ----------
         1 AAAA
         2 BBB

SQL> select a.id, a.location
  2  from xxx a, yyy b
  3  where b.id = a.id (+);

        ID LOCATION
---------- ----------
         1 AAAA
         2 BBB

SQL> select a.id, a.location
  2  from xxx a, yyy b
  3  where a.id = b.id (+);

        ID LOCATION
---------- ----------
         1 AAAA
         2 BBB
         3 BBBB
         4 DDDD