Most correct about case!

Here is one way to elimate 'would-be' duplicates who simply are not because of case sensitivity: 

use strict;

my %unique;
my @email = qw(
   John@foo.com
   john@foo.com
   CAPTELO@microshaft.con
   CAPTELO@microshaft.com
   captntenille@muskrat.com
   CaPtNtEnIlLe@muskrat.com
);

for (@email) {
   my $key = lc $_;
   $unique{$key} = $_ unless ($unique{$key} and $unique{$key} =~ /[A-Z
+]/);
}

print join("\n", values %unique), "\n";

[download]
Yields the list: 
CAPTELO@microshaft.com
CaPtNtEnIlLe@muskrat.com
CAPTELO@microshaft.con
John@foo.com
Of course, this is NOT perfect. Just some random thoughts if you will. ;) If you are not concerned with the extra overhead of space, i recommend storing the email address twice: once as it is, and once all lower-cased. Then you could issue a SQL statement like: 
SELECT distinct lc_email, email, ...
and only use the 'email' column. Actually, even better might be performing a comparison before you insert the email address - make sure that a lower case version of the candidate email address does not already exist in the database first.

jeffa

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)

In reply to (jeffa) 2Re: SQL Results by jeffa
in thread SQL Results by Anonymous Monk

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