From: | Rob Sargent <robjsargent(at)gmail(dot)com> |
---|---|
To: | Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> |
Cc: | pgsql-sql(at)postgresql(dot)org |
Subject: | Re: syntax of joins |
Date: | 2012-04-06 20:14:40 |
Message-ID: | 4F7F4EB0.6050902@gmail.com |
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Thread: | |
Lists: | pgsql-sql |
On 04/06/2012 01:46 PM, Pavel Stehule wrote:
> 2012/4/6 Rob Sargent<robjsargent(at)gmail(dot)com>:
>> On 04/06/2012 01:23 PM, Pavel Stehule wrote:
>>>
>>> Hello
>>>
>>> 2012/4/6 Andreas<maps(dot)on(at)gmx(dot)net>:
>>>>
>>>> hi,
>>>>
>>>> is there a disadvantage to write a join as
>>>>
>>>> select *
>>>> from a, b
>>>> where a.id = b.a_id;
>>>>
>>>
>>>> over
>>>>
>>>> select *
>>>> from a join b on a.id = b.a_id;
>>>>
>>>
>>> yes - newer notation has some advantages
>>>
>>> * clean specification join predicate and filter predicate
>>> * simple adaptability to outer join
>>> * increased protection against copy/paste bug that introduce Cartesian
>>> product
>>>
>>> Regards
>>>
>>> Pavel Stehule
>>>
>>>> --
>>>> Sent via pgsql-sql mailing list (pgsql-sql(at)postgresql(dot)org)
>>>> To make changes to your subscription:
>>>> http://www.postgresql.org/mailpref/pgsql-sql
>>>
>>>
>> In other words, no disadvantage :)
>>
>
> Hard to say - for man who fixed critical cartesian products :) in queries
>
> Pavel
but doesn't there remain "a join b on a.id != b.id"
(I do use the join syntax -- sometimes, honest)
rjs
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