Thanks for the helpful replies so far. I think that maybe I wasn't entirely clear, however. I was thinking of returning a list of distinct objects:

table units:
name      location
------------------
foo_unit  1
foo_unit  2
bar_unit  1
baz_unit  3
[download]

I was hoping to find something like:

$iterator = Package::units->search_distinct(name);
while ($iterator->next) { print };

foo
bar
baz
[download]

While the first suggestion will allow me to do this (thank you), I was hoping that I could find a way to do it without hardcoding each individual query into the class.

Regarding the schema: It is part of an existing project that cannot (easily) be changed.