@Override
    public OrderByAttribute visitOrder_by_reference(SiddhiQLParser.Order_by_referenceContext ctx) {

        Variable variable = (Variable) visit(ctx.attribute_reference());
        if (ctx.order() != null && ctx.order().DESC() != null) {
            return new OrderByAttribute(variable, OrderByAttribute.Order.DESC);
        }
        return new OrderByAttribute(variable);
    }
{@inheritDoc}
<p>
<p>The default implementation returns the result of calling
{@link #visitChildren} on {@code ctx}.</p>
modules/siddhi-query-compiler/src/main/java/io/siddhi/query/compiler/internal/SiddhiQLBaseVisitorImpl.java