[Koha] report help

Can someone help me out here. I need to alter this to show only titles that haven't circulated in X number of years. SELECT b.title, b.author, b.copyrightdate, i.itemcallnumber, i.barcode, i.datelastborrowed, i.issues as totalcheckouts, i.dateaccessioned FROM items i LEFT JOIN issues USING (itemnumber) LEFT JOIN biblio b USING (biblionumber) WHERE i.itemnumber NOT IN (SELECT issues.itemnumber FROM issues) UNION (SELECT b.title, b.author, b.copyrightdate, i.itemcallnumber, i.barcode, i.datelastborrowed, i.issues as totalcheckouts, i.dateaccessioned FROM items i LEFT JOIN issues USING (itemnumber) LEFT JOIN biblio b USING (biblionumber) WHERE i.itemnumber NOT IN (SELECT old_issues.itemnumber FROM old_issues))