// that here to optimize out the "NOT NULL" comparator for NOT NULL columns
if (startingBoundExpr == null) {
AbstractExpression newComparator = new OperatorExpression(ExpressionType.OPERATOR_NOT,
new OperatorExpression(ExpressionType.OPERATOR_IS_NULL), null);
newComparator.getLeft().setLeft(upperBoundComparator.getLeft());
newComparator.finalizeValueTypes();
retval.otherExprs.add(newComparator);
} else {
int lastIdx = retval.indexExprs.size() -1;
retval.indexExprs.remove(lastIdx);