Re: query with table alias
От | Patrick Fiche |
---|---|
Тема | Re: query with table alias |
Дата | |
Msg-id | 016f01c4c8a8$a136a370$2e01a8c0@pc3648pfi обсуждение исходный текст |
Ответ на | query with table alias ("Rodríguez Rodríguez, Pere" <prr@hosppal.es>) |
Список | pgsql-general |
-------------------------------------------------------------------------------------------
Patrick Fiche
email : patrick.fiche@aqsacom.com
tél : 01 69 29 36 18
-------------------------------------------------------------------------------------------
-----Original Message-----
From: pgsql-general-owner@postgresql.org [mailto:pgsql-general-owner@postgresql.org]On Behalf Of Rodríguez Rodríguez, Pere
Sent: vendredi 12 novembre 2004 11:49
To: 'pgsql-general@postgresql.org'
Subject: [GENERAL] query with table aliasHello,
I think I have found a query problem when the query has an alias for a table and use alias item and table name.
I ilustrate the problem with a simple table and query.
prr=# create table foo (c1 int2, c2 int2);
CREATE TABLE
prr=# insert into foo values (1, 1);
INSERT 301891 1
prr=# insert into foo values (2, 2);
INSERT 301892 1
prr=# select * from foo;
c1 | c2
----+----
1 | 1
2 | 2
(2 filas)prr=# select foo.c1, f.c2 from foo f; -- >>> Incorrect result <<<
c1 | c2
----+----
1 | 1
2 | 1
1 | 2
2 | 2
(4 filas)prr=# explain select foo.c1, f.c2 from foo f; -- >>> Incorrect query plan <<<
QUERY PLAN
-------------------------------------------------------------------
Nested Loop (cost=20.00..20040.00 rows=1000000 width=4)
-> Seq Scan on foo f (cost=0.00..20.00 rows=1000 width=2)
-> Materialize (cost=20.00..30.00 rows=1000 width=2)
-> Seq Scan on foo (cost=0.00..20.00 rows=1000 width=2)
(4 filas)The result of the "select foo.c1, f.c2 from foo f" isn't correct, it do a cartesian product of foo table.
My version of PostgreSQL is PostgreSQL 7.4.5 on i386-pc-linux-gnu, compiled by GCC i386-linux-gcc (GCC) 3.3.4 (Debian 1:3.3.4-9).
Is this a bug?, is fixed in posteriors versions?
Thanks in advance,
Protected by Polesoft Lockspam
http://www.polesoft.com/refer.html
В списке pgsql-general по дате отправления: