On Mon, Aug 30, 2021 at 01:47:19PM +0100, Pól Ua Laoínecháin wrote: > I was just wondering if there is some (already written) function out > there that will drop this functionality into my lap? Sure, here: #v+ create function array_dups(ANYARRAY) returns ANYARRAY as $$ select array( select i from unnest($1) i group by i having count(*) > 1 ); $$ language sql; #v- Best regards, depesz