Jeff Frost wrote:
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.
It's interesting, indeed.
Here's how you might do it with a PL/Perl function. :)
CREATE OR REPLACE FUNCTION remove_duplicates(TEXT) RETURNS TEXT AS
$$
my ($text) = @_;
while ($text =~ s/(.)(.*)\1/$1$2/g != 0) {};
return $text;
$$ LANGUAGE plperl;
cww=# SELECT
remove_duplicates('[EMAIL PROTECTED]');
remove_duplicates
-------------------
[EMAIL PROTECTED]
(1 row)
Colin
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