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Re: Hierarchical queries a la Oracle. Patch.

From: Fernando Nasser <fnasser(at)redhat(dot)com>
To: Fernando Nasser <fnasser(at)redhat(dot)com>
Cc: Evgen Potemkin <evgent(at)ns(dot)terminal(dot)ru>,pgsql-patches(at)postgresql(dot)org
Subject: Re: Hierarchical queries a la Oracle. Patch.
Date: 2002-11-26 23:27:43
Message-ID: 3DE4036F.4020705@redhat.com (view raw or flat)
Thread:
Lists: pgsql-patches
Fernando Nasser wrote:> The syntax below is wrong.  Oracle has:
> 
> [START WITH condition] CONNECT BY condition
> 
> not the reverse as stated below.  Maybe this was just a documentation 
> mistake (I haven't looked at the code).
> 
> Fernando
> 
> Evgen Potemkin wrote:
> 
>> + + Syntax.
>> + + SELECT ... FROM ... [ WHERE condition ] CONNECT BY c_expr PRIOR 
>> c_expr START WITH expr +   [ HAVING condition [, ...]] [ LIMIT ... ] [ 
>> OFFSET ... ]
>> + 
> 

Furthermore, PRIOR is not a clause, but a unary operator that must be applied to 
one of the terms of the CONNECT BY expression.

So, we would actually have:

[START WITH expr] CONNECT BY c_expr = PRIOR c_expr
or
[START WITH expr] CONNECT BY PRIOR c_expr = c_expr

(we probably don't want to support operators other than '=')


And there is that '+' in there... what is it for?


So I guess we would be implementing something that is not either the standard 
SQL nor the Oracle syntax.



-- 
Fernando Nasser
Red Hat - Toronto                       E-Mail:  fnasser(at)redhat(dot)com
2323 Yonge Street, Suite #300
Toronto, Ontario   M4P 2C9


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Next:From: Fernando NasserDate: 2002-11-26 23:46:29
Subject: Re: Hierarchical queries a la Oracle. Patch.
Previous:From: Hannu KrosingDate: 2002-11-26 22:21:48
Subject: Re: [HACKERS] Hirarchical queries a la Oracle. Patch.

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