this.effectiveOp = effectiveOp;
}
@Override
public QueryIterator eval(QueryIterator input, final ExecutionContext execCxt) {
return new QueryIterRepeatApply(input, execCxt) {
@Override
protected QueryIterator nextStage(Binding binding) {
QueryIterConcat resultIt = new QueryIterConcat(execCxt);
Collection<NodeRelation> tables = new ArrayList<NodeRelation>();
for (OpTableSQL tableOp: tableOps) {