propsPerGroupByExpr[i] = ExprNodeUtility.getGroupByPropertiesValidateHasOne(new ExprNode[] {groupByNodesValidated[i]});
}
// for each level obtain a separate select expression processor
for (int i = 0; i < numLevels; i++) {
AggregationGroupByRollupLevel level = groupByRollupDesc.getLevels()[i];
// determine properties rolled up for this level
Set<Pair<Integer, String>> rolledupProps = getRollupProperties(level, propsPerGroupByExpr);
ExprNode[] selectClauseLevel = groupByExpressions.getSelectClausePerLevel()[i];