message: Fix bug in physical_piecewise_mergejoin when dealing with NULL values
diff: @@ -194,8 +194,9 @@ PhysicalPiecewiseMergeJoin::PhysicalPiecewiseMergeJoin(LogicalOperator &op, uniq
  static void OrderVector(Vector &vector, PhysicalPiecewiseMergeJoin::MergeOrder &order) {
  // first remove any NULL values; they can never match anyway
  + sel_t not_null_order[STANDARD_VECTOR_SIZE];
  sel_t *result_vector;
  - order.count = Vector::NotNullSelVector(vector, order.order, result_vector);
  + order.count = Vector::NotNullSelVector(vector, not_null_order, result_vector);
  // sort by the join key
  VectorOperations::Sort(vector, result_vector, order.count, order.order);
  }
  