function getJoinedRelation() {
  var relationLeft = lf.proc.Relation.fromRows(sampleEmployees, [e.getName()]);
  var relationRight = lf.proc.Relation.fromRows(sampleJobs, [j.getName()]);
  var joinPredicate = new lf.pred.JoinPredicate(
      e.jobId, j.id, lf.eval.Type.EQ);
  var joinedRelation = joinPredicate.evalRelationsHashJoin(
      relationLeft, relationRight, false);

  joinedRelation.setAggregationResult(lf.fn.avg(j.maxSalary), 50);
  joinedRelation.setAggregationResult(lf.fn.max(j.maxSalary), 100);
  joinedRelation.setAggregationResult(lf.fn.min(j.maxSalary), 0);
  joinedRelation.setAggregationResult(lf.fn.min(e.hireDate), 0);
  joinedRelation.setAggregationResult(lf.fn.max(e.hireDate), 0);

  var entry1 = new lf.proc.RelationEntry(
      new lf.Row(1, {'maxSalary': 1000}), false);
  var entry2 = new lf.proc.RelationEntry(
      new lf.Row(1, {'maxSalary': 2000}), false);
  var distinctRelation = new lf.proc.Relation([entry1, entry2], [j.getName()]);
  joinedRelation.setAggregationResult(
      lf.fn.distinct(j.maxSalary), distinctRelation);

  return joinedRelation;
}
Generates a dummy joined relation, with bogus aggregation results to be used
for tesing.
@return {!lf.proc.Relation}