Re: syntax of joins
От | Rob Sargent |
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Тема | Re: syntax of joins |
Дата | |
Msg-id | 4F7F4EB0.6050902@gmail.com обсуждение исходный текст |
Ответ на | Re: syntax of joins (Pavel Stehule <pavel.stehule@gmail.com>) |
Список | pgsql-sql |
On 04/06/2012 01:46 PM, Pavel Stehule wrote: > 2012/4/6 Rob Sargent<robjsargent@gmail.com>: >> On 04/06/2012 01:23 PM, Pavel Stehule wrote: >>> >>> Hello >>> >>> 2012/4/6 Andreas<maps.on@gmx.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@postgresql.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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