Dear Gnanavel,
(please reply to the lists...)
Indeed it works!
Still, I think it's a bug.
As for this solution being a workaround, it's a bit of pain, since the
subselect names (effectively, the included subselects) are not constant.
As for my workaround, I used a condition to not include the last WHERE
clause in the query when the inner WHERE clauses are present (since it does
nothing).
--
G.
On 2005.05.24. 13:14, Gnanavel Shanmugam wrote:
replace
WHERE a+b = 3;
with
WHERE aa.a+aa.b = 3;
(or)
WHERE bb.a+bb.b = 3;
with regards,
S.Gnanavel
-----Original Message-----
From: [EMAIL PROTECTED]
Sent: Tue, 24 May 2005 12:39:04 +0200
To: pgsql-bugs@postgresql.org, pgsql-sql@postgresql.org
Subject: Re: [SQL] could not devise a query plan
Dear Gurus,
Sorry for upping a 13-month-old thread; please tell if I should've opened
another one.
Here I come again, with another silly join. Please forgive me, but our
queries are built from blocks :)
VERSION: 7.4.6, 7.4.8, 8.0.0rc4 (sorry, no newer installed right now)
ABSTRACT: The following query fails.
SELECT * FROM
(SELECT a,b FROM cdqp WHERE a=1 AND b=2) AS aa
NATURAL FULL JOIN
(SELECT a,b FROM cdqp WHERE a=1 and b=2) AS bb
WHERE a+b = 3;
DETAILS: It seems it's something about the redundant WHERE clauses. If I
comment (replace with "WHERE true") any of the three WHERE clauses, it
works.
Session log: See below.
TIA,
--
G.
serv1:tir=> \d cdqp
Table "pg_temp_20.cdqp"
Column | Type | Modifiers
--------+---------+-----------
a | integer |
b | integer |
serv1:tir=> SELECT * FROM
serv1:tir-> (SELECT a,b FROM cdqp WHERE a=1 AND b=2) AS aa
serv1:tir-> NATURAL FULL JOIN
serv1:tir-> (SELECT a,b FROM cdqp WHERE a=1 and b=2) AS bb
serv1:tir-> WHERE a+b = 3;
ERROR: could not devise a query plan for the given query
serv1:tir=> SELECT * FROM
serv1:tir-> (SELECT a,b FROM cdqp WHERE a=1 AND b=2) AS aa
serv1:tir-> NATURAL FULL JOIN
serv1:tir-> (SELECT a,b FROM cdqp WHERE a=1 and b=2) AS bb
serv1:tir-> WHERE true;
a | b
---+---
1 | 2
(1 row)
---------------------------(end of broadcast)---------------------------
TIP 9: the planner will ignore your desire to choose an index scan if
your
joining column's datatypes do not match
---------------------------(end of broadcast)---------------------------
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