public void visit(LOGreaterThan op) throws VisitorException {
ExpressionOperator left = op.getLhsOperand();
ExpressionOperator right = op.getRhsOperand();
GreaterThanExpression eq = new GreaterThanExpression
(exprPlan, exprOpsMap.get(left), exprOpsMap.get(right));
exprOpsMap.put(op, eq);
}