ValueExpression<Double> substract = new Subtraction(
new ValueSpecification(_doubleConv, 1.0), new ColumnReference(_doubleConv, 8));
//extendedPrice*(1-discount)
ValueExpression<Double> product = new Multiplication(new ColumnReference(_doubleConv, 7),
substract);
AggregateOperator agg = new AggregateSumOperator(product, conf)
//.setGroupByColumns(Arrays.asList(0, 1, 4, 6, 2, 3, 5));
.setGroupByColumns(Arrays.asList(0, 1, 4, 6, 2, 3, 5));
ColumnReference colC_O_N = new ColumnReference(_ic, 6);
ColumnReference colL = new ColumnReference(_ic, 0);