Inconsistent results with ANSI LEFT JOIN on 9iR2

Question

Is this a known issue? Is it solved in 10g?
With the following data setup, I get inconsistent results. It seems to be linked to the combination of using LEFT JOIN with the NULL comparison within the JOIN.
create table titles (title_id int, title varchar(50));
insert into titles values (1, 'Red Book');
insert into titles values (2, 'Yellow Book');
insert into titles values (3, 'Blue Book');
insert into titles values (4, 'Orange Book');
create table sales (stor_id int, title_id int, qty int, email varchar(60));
insert into sales values (1, 1, 1, '[email protected]'));
insert into sales values (1, 2, 1, '[email protected]');
insert into sales values (3, 3, 4, null);
insert into sales values (3, 4, 5, '[email protected]');
SQL> SELECT titles.title_id, title, qty
2 FROM titles LEFT OUTER JOIN sales
3 ON titles.title_id = sales.title_id
4 AND stor_id = 3
5 AND sales.email is not null
6 ;
TITLE_ID TITLE QTY
4 Orange Book 5
3 Blue Book
1 Red Book
2 Yellow Book
SQL>
SQL> SELECT titles.title_id, title, qty
2 FROM titles LEFT OUTER JOIN sales
3 ON titles.title_id = sales.title_id
4 AND 3 = stor_id
5 AND sales.email is not null;
TITLE_ID TITLE QTY
2 Yellow Book 1
4 Orange Book 5
3 Blue Book
1 Red Book
It seems to matter what order I specify the operands stor_id = 3, or 3 = stor_id.
In the older (+) environment, I would understand this, but here? I'm pretty sure most other databases don't care about the order.
thanks for your insight
Kevin

Answer 1

Don't have a 9i around right now to test ... but in 10 ...
SQL> create table titles (title_id int, title varchar(50));
 
Table created.
 
SQL> insert into titles values (1, 'Red Book');
 
1 row created.
 
SQL> insert into titles values (2, 'Yellow Book');
 
1 row created.
 
SQL> insert into titles values (3, 'Blue Book');
 
1 row created.
 
SQL> insert into titles values (4, 'Orange Book');
 
1 row created.
 
SQL> create table sales (stor_id int, title_id int, qty int, email varchar(60));
 
Table created.
 
SQL> insert into sales values (1, 1, 1, '[email protected]');
 
1 row created.
 
SQL> insert into sales values (1, 2, 1, '[email protected]');
 
1 row created.
 
SQL> insert into sales values (3, 3, 4, null);
 
1 row created.
 
SQL> insert into sales values (3, 4, 5, '[email protected]');
 
1 row created.
 
SQL> SELECT titles.title_id, title, qty
  2   FROM titles LEFT OUTER JOIN sales
  3   ON titles.title_id = sales.title_id
  4   AND stor_id = 3
  5   AND sales.email is not null
  6   ;
 
  TITLE_ID TITLE                                                     QTY
         4 Orange Book                                                 5
         3 Blue Book
         1 Red Book
         2 Yellow Book
 
SQL>
SQL> SELECT titles.title_id, title, qty
  2   FROM titles LEFT OUTER JOIN sales
  3   ON titles.title_id = sales.title_id
  4   AND 3 = stor_id
  5   AND sales.email is not null;
 
  TITLE_ID TITLE                                                     QTY
         4 Orange Book                                                 5
         3 Blue Book
         1 Red Book
         2 Yellow Book
SQL> exit
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