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Re: can subqueries be executed first in SPARQL?

From: james anderson <james@dydra.com>
Date: Mon, 27 Jun 2016 15:28:43 +0000
Message-ID: <01020155927a1a16-32baf277-1ba6-4779-bd74-b89a7decdfe6-000000@eu-west-1.amazonses.com>
To: public-sparql-dev@w3.org

> On 2016-06-27, at 16:05, Peter F. Patel-Schneider <pfpschneider@gmail.com> wrote:
> 
> […]
> 
> Project(
>  { (x,:b) |
>    eval( D(G),
>      substitute(
>        Join(
>          Extend( Z, y, :c ) ,
>          ToMultiset( Project( ToList( BGP(?z :d ?x) ) , z ) )
>          )
>        (x,:b) )
>      ) /= { } } ,
>  x
>  )
> 
> Project(
>  { (x,:b) |
>    eval( D(G),
>        Join(
>          Extend( Z, y, :c ) ,
>          ToMultiset( Project( ToList( BGP(?z :d :b) ) , z ) )
>          )
>      ) /= { } } ,
>  x
>  )

if i follow this, this reduction obtains iff the project has no effect on the scope the binding for ?x which was established by the outer extend.
is that intended?

best regards, from berlin,


---
james anderson | james@dydra.com | http://dydra.com
Received on Monday, 27 June 2016 15:29:18 UTC

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