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
