From: | Steve Atkins <steve(at)blighty(dot)com> |
---|---|
To: | pgsql-general General <pgsql-general(at)postgresql(dot)org> |
Subject: | Re: CIDR data type query help |
Date: | 2010-05-19 18:17:36 |
Message-ID: | 4C512C56-FA89-4634-8F3E-25F1DE839A80@blighty.com |
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Lists: | pgsql-general |
On May 19, 2010, at 10:32 AM, Scot Kreienkamp wrote:
> Hi everyone,
>
> I have a column of type CIDR in a table that I am querying that contains
> the values of 10/8, 10.1/16,10.1.28/24, and 10.1.28.95. I am trying to
> return only the one record that's most specific compared to the IP
> address I'm currently on as this is being done in a CGI script. If
> there's no specific match for the IP of the originating workstation then
> it should return the /24 if it's there, then the /16 if it's there, etc.
> I have never worked with the CIDR type, and a novice when it comes to
> SQL query language, so I have no idea how to approach this.
Something like this (untested):
select foo from table where foo >>= '10.1.28.14' order by masklen(foo) desc limit 1;
You likely want to look at http://pgfoundry.org/projects/ip4r/ as an alternative,
if the table is likely to grow beyond a few dozen rows. It's usefully indexable
for "contains" queries, unlike the native cidr type,
Cheers,
Steve
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