strange behvaviour in join? BUG in 7.02?
I have PSQL 7.02
classic join on Two tables:
select l.id from linia l,lk_strefa2linia lk
where l.id = lk.fk_linia and lk.fk_strefa=5;
gives correct linia.ids.
but
select linia.id from linia l,lk_strefa2linia lk
where l.id = lk.fk_linia and lk.fk_strefa=5;
(the only difference is second word: linia.id instead l.id)
will give totaly different results).
tables definitions:
mlotdev=> \d lk_strefa2linia
Table "lk_strefa2linia"
Attribute | Type | Modifier
-----------+---------+----------
fk_strefa | integer | not null
fk_linia | integer | not null
Index: lk_strefa2linia_ukeymlotdev=> \d linia
Table "linia"
Attribute | Type | Modifier
-----------+-------------+---------------------------------------------
id | integer | not null default nextval('seq_linia'::text)
fk_typ | integer | not null
numer | char(10) | not null
status | char(1) | not null default '?'
stamp | timestamp | not null default now()
opis | varchar(64) | not null
skrot | varchar(16) | not null
Index: linia_pkeyPlease CC answer to me. Thanx!
--
radoslaw.stachowiak.........................................http://alter.pl/
Radoslaw Stachowiak wrote:
I have PSQL 7.02
classic join on Two tables:
select l.id from linia l,lk_strefa2linia lk
where l.id = lk.fk_linia and lk.fk_strefa=5;gives correct linia.ids.
but
select linia.id from linia l,lk_strefa2linia lk
where l.id = lk.fk_linia and lk.fk_strefa=5;(the only difference is second word: linia.id instead l.id)
will give totaly different results).
You are actually doing a 3-way join, with linia included twice.
It is implicitly included a second time when a column is referenced
from it without the alias.
--
Oliver Elphick Oliver.Elphick@lfix.co.uk
Isle of Wight http://www.lfix.co.uk/oliver
PGP: 1024R/32B8FAA1: 97 EA 1D 47 72 3F 28 47 6B 7E 39 CC 56 E4 C1 47
GPG: 1024D/3E1D0C1C: CA12 09E0 E8D5 8870 5839 932A 614D 4C34 3E1D 0C1C
========================================
"But thanks be to God, which giveth us the victory
through our Lord Jesus Christ."
I Corinthians 15:57
Import Notes
Reply to msg id not found: MessagefromRadoslawStachowiakradek@alter.plofFri10Nov2000114320+0100.20001110114320.J5821@blue.alter.pl | Resolved by subject fallback
"Oliver Elphick" <olly@lfix.co.uk> writes:
You are actually doing a 3-way join, with linia included twice.
It is implicitly included a second time when a column is referenced
from it without the alias.
7.1 will provide a NOTICE that's intended to alert people that such
constructs probably don't do what they're expecting:
regression=# select f.f1, int4_tbl.f1 from int4_tbl f;
NOTICE: Adding missing FROM-clause entry for table "int4_tbl"
although I wonder whether this will leave the query author any
less confused :-(.
regards, tom lane