Re: Basic Query Question

From: Ramy Abdel-Azim <ramy(dot)abdel-azim(at)startdatelabs(dot)com>
To: Jude Lucien <jlucien(at)gmail(dot)com>
Cc: pgsql-novice(at)postgresql(dot)org
Subject: Re: Basic Query Question
Date: 2011-12-07 21:16:24
Message-ID: 4EDFD7A8.7040303@startdatelabs.com
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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
>>>
>>>
>>>
>>
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>

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