Please disregard the previous email. After rereading what you sent, I realized that I need an outer join to A2 and not
simplya self join...thanks and my apologies!
----- Original Message ----
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Heikki Linnakangas <heikki@enterprisedb.com>
Cc: Marcus Torres <marcsf23@yahoo.com>; pgsql-bugs@postgresql.org
Sent: Wednesday, February 13, 2008 7:40:32 AM
Subject: Re: [BUGS] BUG #3958: Self-Join Group-By Clause Produces Incorrect Results
"Heikki
Linnakangas"
<heikki@enterprisedb.com>
writes:
>
Marcus
Torres
wrote:
>>
I
wrote
a
simple
self-join
query
to
sum
the
transaction
count
of
different
>>
types
of
records
in
a
audit
table
and
the
result
set
for
the
different
sum
>>
totals
was
the
same
which
is
incorrect.
>
Looks
perfectly
correct
to
me.
Me
too.
The
underlying
data
before
grouping/aggregation
is
regression=#
select
A1.AUDIT_DATE,
P.CONTENT_POLICY_NAME,
A1.TXN_COUNT,
A2.TXN_COUNT
FROM
T_AUDIT
A1,
T_AUDIT
A2,
T_POLICY
P
WHERE
P.ID
=
A1.POLICY_ID
AND
P.ID
=
A2.POLICY_ID
AND
A1.POLICY_ID
=
A2.POLICY_ID
AND
A1.AUDIT_DATE
=
A2.AUDIT_DATE
AND
A1.AUDIT_TYPE_CODE
=
'CONTENT_1'
AND
A2.AUDIT_TYPE_CODE
=
'CONTENT_2';
audit_date
|
content_policy_name
|
txn_count
|
txn_count
------------+---------------------+-----------+-----------
2008-01-01
|
TEST
POLICY
|
1
|
1
2008-01-01
|
TEST
POLICY
|
1
|
1
2008-01-01
|
TEST
POLICY
|
1
|
1
2008-01-01
|
TEST
POLICY
|
1
|
1
2008-01-01
|
TEST
POLICY
|
1
|
1
2008-01-01
|
TEST
POLICY
|
1
|
1
2008-01-01
|
TEST
POLICY
|
1
|
1
2008-01-01
|
TEST
POLICY
|
1
|
1
2008-01-01
|
TEST
POLICY
|
1
|
1
2008-01-01
|
TEST
POLICY
|
1
|
1
(10
rows)
from
which
it's
clear
that
given
all
ones
in
txn_count,
the
sums
*must*
be
the
same
because
they're
taken
over
the
same
number
of
rows.
I
suspect
what
the
OP
needs
is
two
separate
queries
(perhaps
union'ed
together)
not
a
self-join.
regards,
tom
lane
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