Re: JOIN producing duplicate results

I figured it out. The problem was that osvermap has an arch column,
such that there are more than one of the same osversion and the arch
differs. Adding this eliminated the duplicates: o.arch=a.arch

Here's the fixed working query:

SELECT
a.id
, a.suiteid
, a.testname
, date_trunc('second', a.last_update) AS last_update
, regexp_replace(p.relname, E'tests', '', 'g')
, o.osname
FROM
smoketests AS a
, pg_class AS p
, smoke AS t
, osversmap AS o
WHERE
o.arch=a.arch
AND a.osversion = o.osversion
AND a.suiteid = t.id
AND a.tableoid = p.oid
AND a.current_status = 'FAILED'
AND a.arch = 'i386'
AND a.os = 'Darwin'
AND a.last_update > '2012-05-01 04:00:00'
AND a.last_update < '2012-05-02 14:20:45'
ORDER BY
a.id ;

On Thu, May 3, 2012 at 6:53 AM, Oliveiros d'Azevedo Cristina
<oliveiros(dot)cristina(at)marktest(dot)pt> wrote:
> Do you have any table inheriting from smoketests?
>
> Best,
> Oliveiros
>
> ----- Original Message ----- From: "Brent Dombrowski"
> <brent(dot)dombrowski(at)gmail(dot)com>
> To: "Lonni J Friedman" <netllama(at)gmail(dot)com>
> Cc: <pgsql-novice(at)postgresql(dot)org>
> Sent: Thursday, May 03, 2012 2:22 PM
> Subject: Re: [NOVICE] JOIN producing duplicate results
>
>
>
> You are not using a.id in the join. My guess is that all the other columns
> in a that you are joining against are not unique and that is where the
> duplicates are coming from.
>
> Brent.
>
> On May 2, 2012, at 4:51 PM, Lonni J Friedman wrote:
>
>> I've got a query that is joining data across 4 tables to provide data
>> based on test results.  The query is working fine, except for the fact
>> that its returning two identical records for each row of unique data.
>> If I throw a DISTINCT in front of the primary key column (a.id) of
>> one of the tables in the join, that eliminates all the duplicates.
>> However, I've read (and found) that DISTINCT tends to introduce a
>> performance hit, so I'm hoping to find a better performing solution,
>> if possible.  Hopefully I'm just doing something silly with my JOINS
>> that is easily fixed.  This is on postgresql-9.0.x, and yes I'm aware
>> that if i upgraded to 9.1.x then I could likely do a 'group by a.id',
>> but for now I'm stuck on 9.0.x.
>>
>> Here's the query:
>> SELECT a.id,a.suiteid,a.testname,date_trunc('second',a.last_update) AS
>> last_update,regexp_replace(p.relname,E'tests','','g'),o.osname
>> FROM smoketests AS a, pg_class AS p, smoke AS t, osversmap AS o
>> WHERE a.osversion=o.osversion AND a.suiteid=t.id AND a.tableoid=p.oid
>> AND ( a.current_status='FAILED' ) AND ( a.arch='i386' ) AND (
>> a.os='Darwin' ) AND a.last_update>'2012-05-01 04:00:00' AND
>> a.last_update<'2012-05-02 14:20:45'
>> ORDER BY a.id ;
>>
>>   id    | suiteid |     testname     |     last_update     |
>> regexp_replace |   osname
>>
>> ----------+---------+------------------+---------------------+----------------+------------
>> 32549818 |  668232 | bug377064        | 2012-05-01 08:38:07 | smoke
>>  | OSX-10.7.x
>> 32549818 |  668232 | bug377064        | 2012-05-01 08:38:07 | smoke
>>  | OSX-10.7.x
>> 32549819 |  668232 | funcmem_resize   | 2012-05-01 08:38:07 | smoke
>>  | OSX-10.7.x
>> 32549819 |  668232 | funcmem_resize   | 2012-05-01 08:38:07 | smoke
>>  | OSX-10.7.x
>> 32549820 |  668232 | leitest | 2012-05-01 08:38:07 | smoke      |
>> OSX-10.7.x
>> 32549820 |  668232 | leitest | 2012-05-01 08:38:07 | smoke      |
>> OSX-10.7.x
>>
>> The problem is visible in the id column, where there are two of each
>> value returned even though a.id is the unique primary key of the smoke
>> table and doesn't really have duplicates.  The 'smoke' table has a one
>> to many relationship with the smoketests table, but I'm still rather
>> confused why I'm getting the duplicates of everything.
>>