From: Harald Fuchs <hari.fuchs@gmail.com>
To: pgsql-sql@postgresql.org
Subject: Re: How to search for a part of a number
Date: Mon, 25 Oct 2010 15:13:51 +0200
Message-ID: <86tykao1o0.fsf@mgm.protecting.net> (raw)
References: <4CC4D3E2.7090302@gmx.net>
In article <4CC4D3E2.7090302@gmx.net>,
Andreas <maps.on@gmx.net> writes:
> Hi,
> I'm wondering if there was a clever way to find parts of a numeric
> string in another table.
> There is a table that holds city-codes and city-names. City-code would
> be the part of a phone number that identifies the city.
> Over here this code can have 2 - 5 digits. So the table would contain:
> 23 ; A-City
> 345 ; B-Town
> 4455 ; C-Village
> 632 ; D-Town
> ...
> I'm quite sure the numbering system is bound to be spanning a search tree.
> So there are 2 tasks:
> a) I'd get 445598765 in and like to know the corresponding city
If the prefixes are unique:
SELECT code, name
FROM tbl
WHERE '445598765' LIKE code || '%'
If not:
SELECT code, name
FROM tbl
WHERE '445598765' LIKE code || '%'
ORDER BY length(code) DESC
LIMIT 1
If your table is so large that seqscans hurt you, use the 'prefix'
contrib package.
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To: pgsql-sql@postgresql.org
Cc: hari.fuchs@gmail.com
Subject: Re: How to search for a part of a number
In-Reply-To: <86tykao1o0.fsf@mgm.protecting.net>
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