Possible SELECT bug in 7.0.2

Hello,

While working on the next release of Tangram, I have encountered the
following problem in version 7.0.2. Given the following tables:

Springfield=> select version();                           version
---------------------------------------------------------------PostgreSQL 7.0.2 on i686-pc-linux-gnu, compiled by gcc
2.95.2
(1 row)
Springfield=> select * from Person; id  | classid
------+---------1006 |       62006 |       63006 |       64006 |       65006 |       6
(5 rows)
Springfield=> select * from NP; id  | ia_ref | credit | name | firstname | ia_slot | is_ref | partner | age
------+--------+--------+------+-----------+---------+--------+---------+-----1006 |        |        |      | Bart
|        |        |         |2006 |        |        |      | Lisa      |         |        |         |3006 |        |
   |      | Maggie    |         |        |         |5006 |        |        |      | Marge     |         |        |
  |4006 |        |        |      | Homer     |         |        |         |
 
(5 rows)
Springfield=> select * from s_children;coll | item
------+------5006 | 30065006 | 10065006 | 20064006 | 10064006 | 30064006 | 2006
(6 rows)

...I run the following two queries:

Springfield=> SELECT t4.firstName       FROM Person t1, NP t2, s_children tl1001, Person t3, NP t4       WHERE
(tl1001.coll= t1.id AND tl1001.item = t3.id)       AND t2.id = t1.id AND t4.id = t3.id;firstname
 
-----------BartBartMaggieMaggie
(4 rows)
Springfield=> SELECT t2.firstName, t4.firstName       FROM Person t1, NP t2, s_children tl1001, Person t3, NP t4
WHERE(tl1001.coll = t1.id AND tl1001.item = t3.id)       AND t2.id = t1.id AND t4.id = t3.id;firstname | firstname
 
-----------+-----------Homer     | BartHomer     | LisaHomer     | Maggie
(3 rows)

Both result sets seem wrong; even more bizarre, adding a column in the
projection affects the result set.

In addition, Tangram's test suite runs flawlessly against Sybase,
Mysql, Oracle and Postgres 6.4.2.
-- 
Jean-Louis Leroy
http://users.skynet.be/jll