Re: finding columns that have three or fewer distinct characters

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(at)frostconsultingllc(dot)com>
Frost Consulting, LLC http://www.frostconsultingllc.com/
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