How to find Duplicate records in a table?

var dupRecords = [];

var gaDupCheck1 = new GlideAggregate('sys_user'); gaDupCheck1.addAggregate('COUNT', 'email');

gaDupCheck1.groupBy('email');

gaDupCheck1.addHaving('COUNT', '>', 1);

gaDupCheck1.query();

while (gaDupCheck1.next()) {

dupRecords.push(gaDupCheck1.email.toString());

}

gs.print(dupRecords);