Select all duplicates from SQLite

IB2017 has asked for the wisdom of the Perl Monks concerning the following question:

Hello monks

I want to select all duplicates from my database. I am using the following:

my $duplicates= $dbh->selectall_arrayref("SELECT ID, Tag1, Tag2, COUNT
+(*) c FROM table GROUP BY Tag1, Tag2 HAVING c > 1");
[download]

This identifies if two (or more) entries are duplicates (Tag1 and Tag2 in combination), however it retrieves only the first (?) occurrence, not all duplicated entries. If I have:

1:science:math
2:science:algebra
3:history:math
4:science:math
[download]

The select statement returns 1:science:math, not 4:science:math. Is there a way to change it in order to have in my array all duplicates?

Back to Seekers of Perl Wisdom