From: Jeff Frost <jeff@frostconsultingllc.com>
To: Osvaldo Rosario Kussama <osvaldo.kussama@gmail.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: finding columns that have three or fewer distinct characters
Date: Wed, 5 Mar 2008 12:03:03 -0800 (PST)
Message-ID: <Pine.LNX.4.64.0803051202440.4804@discord.home.frostconsultingllc.com> (raw)
In-Reply-To: <47CEEAA3.3040004@gmail.com>
References: <Pine.LNX.4.64.0803050912570.4804@discord.home.frostconsultingllc.com>
<47CEEAA3.3040004@gmail.com>
On Wed, 5 Mar 2008, Osvaldo Rosario Kussama wrote:
> Jeff Frost escreveu:
>> I've got an interesting one...I'm trying to find columns that have three or
>> fewer distinct characters (for example, "aaaaaaaaaa"). Wondering if I need
>> to write a function or if someone has an idea how to do it with built in
>> functions and/or pattern matching?
>>
>> I think the thing to do would be to lowercase everything, then remove all
>> duplicate chars and spaces, then use length() on that, but it's not obvious
>> to me how I might remove the duplicate chars with the pattern matching
>> support in the docs.
>>
>
> Try:
> SELECT
> array_to_string(array(
> SELECT DISTINCT lower(substr('aabbcdddef AB',i,1))
> FROM generate_series(1,length('aabbcdddef AB'))
> s(i))
> , '');
>
Osvaldo, that appears to work perfectly! Thank you much!
--
Jeff Frost, Owner <jeff@frostconsultingllc.com>
Frost Consulting, LLC http://www.frostconsultingllc.com/
Phone: 650-780-7908 FAX: 650-649-1954
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To: pgsql-sql@postgresql.org
Cc: jeff@frostconsultingllc.com, osvaldo.kussama@gmail.com
Subject: Re: finding columns that have three or fewer distinct characters
In-Reply-To: <Pine.LNX.4.64.0803051202440.4804@discord.home.frostconsultingllc.com>
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