Skip site navigation (1) Skip section navigation (2)

Re: Basic Query Question

From: Jude Lucien <jlucien(at)gmail(dot)com>
To: Ramy Abdel-Azim <ramy(dot)abdel-azim(at)startdatelabs(dot)com>
Cc: pgsql-novice(at)postgresql(dot)org
Subject: Re: Basic Query Question
Date: 2011-12-07 21:20:19
Message-ID: CAPRXF2rTenm04BOy6PQgKWsCM-ECsnLr2afeWYCk7ANc4hAcZQ@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-novice
That query doesn't work for me as I can't make seem to add "WHERE
model='model'" to the query if I use a JOIN.


On 7 December 2011 21:16, Ramy Abdel-Azim
<ramy(dot)abdel-azim(at)startdatelabs(dot)com> wrote:
> try it out and let us know.
> we anxiously await your reply ;-)
>
>
> On 12/7/11 4:15 PM, Jude Lucien wrote:
>>
>> I've just realised why it may not be working - bike_id is not the
>> primary key of booking.  booking_id is.
>>
>> I was getting results, just not the correct ones.  There are 23 bikes
>> of a certain model, two of which are booked on a certain date.  My
>> query should then return 21 bike_id's.
>>
>> Can I even do a join if booking.bike_id is not the primary key?
>>
>>
>> On 7 December 2011 21:02, Ramy Abdel-Azim
>> <ramy(dot)abdel-azim(at)startdatelabs(dot)com>  wrote:
>>>
>>> i'm not sure but i think not being explicit about the join causes psql to
>>> try to join on ID.
>>>
>>> What are you getting? an error or an empty result set?
>>>
>>> I would think you should do the join explicitly like this:
>>>
>>> select bike.bike_id from bike  join booking on bike.bike_id =
>>> booking.bike_id where booking.date != '2011-11-20'
>>>
>>>
>>> On 12/7/11 3:55 PM, Jude Lucien wrote:
>>>>
>>>> Sorry for the basic question, I can't seem to figure it out.
>>>>
>>>> I have two tables, booking and bike.  Both have bike_id as primary key.
>>>>
>>>> I am trying to return all bike_id's where bike.model='Kona' AND
>>>> booking.booking_date DOES NOT EQUAL 'date';
>>>>
>>>> My query is as follows:
>>>>
>>>> SELECT bike.bike_id FROM bike,booking WHERE bike.model='model' AND
>>>> booking.booking_date!='2011-11-20' AND bike.bike_id=booking.bike_id;
>>>>
>>>> Any help appreciated!
>>>>
>>>> Jude
>>>>
>>>>
>>>>
>>>
>>> --
>>> Sent via pgsql-novice mailing list (pgsql-novice(at)postgresql(dot)org)
>>> To make changes to your subscription:
>>> http://www.postgresql.org/mailpref/pgsql-novice
>>
>>
>>
>



-- 
"None are more hopelessly enslaved than those who falsely believe they
are free"  -- Johann Wolfgang von Goethe

In response to

Responses

pgsql-novice by date

Next:From: Ramy Abdel-AzimDate: 2011-12-07 21:22:47
Subject: Re: Basic Query Question
Previous:From: Ramy Abdel-AzimDate: 2011-12-07 21:16:24
Subject: Re: Basic Query Question

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group