Performing an aggregation for a set of nodes that match an expression is fairly simple. However, performing the same aggregation for only unique items introduces more complexity. For the sample XML snippet, <applicant> <address_details> <court_judgements id="CJR" title="MRS" forename="R" surname=" JONES" value="42300" type="CJP" case_number="6XT01ZZZ"/> <court_judgements id="CJR" title ... [Read more]