On Nov 1, 2007, at 18:57, Tom Lane wrote:
In the usual tradition of SQL99, the spec text is enormously less
readable than SQL92 was, but I *think* this says nearly the same thing
as what we do: a plain column reference in ORDER BY is first sought as
an output column name, and failing that
Chris Browne wrote:
If I replicate your query, with extra columns, AND NAMES, I get the following:
[EMAIL PROTECTED]:5433=# select random() as r1, random() as r2, random() as
r3 from generate_series(1,10) order by random();
r1 | r2 |r3
Dear sirs,
I was very surprised when I executed such SQL query (under PostgreSQL 8.2):
select random() from generate_series(1, 10) order by random();
I thought I would receive ten random numbers in random order. But I received
ten random numbers sorted numerically:
random
piotr_sobolewski wrote:
Dear sirs,
I was very surprised when I executed such SQL query (under PostgreSQL 8.2):
select random() from generate_series(1, 10) order by random();
I thought I would receive ten random numbers in random order. But I received
ten random numbers sorted numerically:
-Original Message-
From: [EMAIL PROTECTED] [mailto:pgsql-general-
[EMAIL PROTECTED] On Behalf Of piotr_sobolewski
Sent: Thursday, November 01, 2007 9:25 AM
To: pgsql-general@postgresql.org
Subject: [GENERAL] select random order by random
Dear sirs,
I was very surprised when I
On 11/1/07, Lee Keel [EMAIL PROTECTED] wrote:
Dear sirs,
I was very surprised when I executed such SQL query (under PostgreSQL
8.2):
select random() from generate_series(1, 10) order by random();
I thought I would receive ten random numbers in random order. But I
received
ten
Scott Marlowe [EMAIL PROTECTED] writes:
I think that Piotr expected the random() to be evaluated in both
places separately.
My guess is that it was recognized by the planner as the same function
and evaluated once per row only.
If you try this:
select random() from generate_series(1, 10)
Gregory Stark wrote:
Scott Marlowe [EMAIL PROTECTED] writes:
I think that Piotr expected the random() to be evaluated in both
places separately.
My guess is that it was recognized by the planner as the same function
and evaluated once per row only.
If you try this:
select random() from
On Thu, Nov 01, 2007 at 04:49:16PM +, Richard Huxton wrote:
Gregory Stark wrote:
This does strike me as wrong. random() is marked volatile and the planner
ought not collapse multiple calls into one.
I think I agree with the earlier poster. Surely these two queries should
be
Richard Huxton [EMAIL PROTECTED] writes:
Gregory Stark wrote:
This does strike me as wrong. random() is marked volatile and the planner
ought not collapse multiple calls into one.
I think I agree with the earlier poster. Surely these two queries should
be equivalent?
SELECT random()
On Thursday 01 November 2007 17:08, brian wrote:
I was very surprised when I executed such SQL query (under PostgreSQL
8.2): select random() from generate_series(1, 10) order by random();
I don't understand - why the result is like that? It seems like in each
row both random()s were
On Thursday 01 November 2007 17:16, Scott Marlowe wrote:
I was very surprised when I executed such SQL query (under PostgreSQL
8.2):
select random() from generate_series(1, 10) order by random();
(...)
My guess is that it was recognized by the planner as the same function
and
On Thu, Nov 01, 2007 at 02:22:58PM -0400, Tom Lane wrote:
SELECT random()FROM generate_series(1, 10) ORDER BY random();
SELECT random() AS foo FROM generate_series(1, 10) ORDER BY foo;
(BTW, this is not the planner's fault; the collapsing of the two
targetlist entries into one
On 11/1/07, Martijn van Oosterhout [EMAIL PROTECTED] wrote:
On Thu, Nov 01, 2007 at 02:22:58PM -0400, Tom Lane wrote:
SELECT random()FROM generate_series(1, 10) ORDER BY random();
SELECT random() AS foo FROM generate_series(1, 10) ORDER BY foo;
(BTW, this is not the planner's
Martijn van Oosterhout [EMAIL PROTECTED] writes:
Something twigged telling me that in fact the latter expression is not
in standard SQL but a (very common) extension. A sort key is clearly
indicated to be a value expression with no indication anywhere that
column aliases are allowed here
Scott Marlowe [EMAIL PROTECTED] writes:
On 11/1/07, Martijn van Oosterhout [EMAIL PROTECTED] wrote:
On Thu, Nov 01, 2007 at 02:22:58PM -0400, Tom Lane wrote:
SELECT random()FROM generate_series(1, 10) ORDER BY random();
SELECT random() AS foo FROM generate_series(1, 10) ORDER BY
Gregory Stark [EMAIL PROTECTED] writes:
So I guess having the parser do this substitution kind of makes sense
if you're thinking about things the way the spec does. It doesn't make
much sense if you're thinking the way Postgres does of having
arbitrary expressions there independent of what's
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