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List:       postgresql-sql
Subject:    Re: [SQL] Determining if two subnets intersect
From:       Florian Weimer <Florian.Weimer () RUS ! Uni-Stuttgart ! DE>
Date:       2001-07-25 7:17:23
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Tom Lane <tgl@sss.pgh.pa.us> writes:

> Florian Weimer <Florian.Weimer@RUS.Uni-Stuttgart.DE> writes:
> > Is there some efficient PostgreSQL expression which is true if and
> > only if two subnets (given as values of type cidr) have non-empty
> > intersection (even if the intersection is not a CIDR network)?
> 
> Maybe I'm missing something, but ISTM it's only possible for two
> CIDR subnets to overlap if one contains the other.  So you could
> check with
> 
> 		A <<= B OR B <<= A

Oh, I think you are right; I haven't paid attention.  Thanks.

-- 
Florian Weimer 	                  Florian.Weimer@RUS.Uni-Stuttgart.DE
University of Stuttgart           http://cert.uni-stuttgart.de/
RUS-CERT                          +49-711-685-5973/fax +49-711-685-5898

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