@Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        String orderStr = order.stream().map(array -> A.empty().equals(array[0])
                                                      ? Text.format("%s %s", array[1], array[2])
                                                      : Text.format("%s%s %s", array[0], array[1], array[2]))
            .collect(Collectors.joining(", "));

        String others = map.entrySet().stream()
            .filter(entry -> entry.getValue() != null)
            .map(entry -> entry.getKey() + " " + entry.getValue())
            .collect(Collectors.joining(" "));

        if (orderStr.isEmpty()) {
            sb.append(others.isEmpty() ? "" : others);
        } else if (others.isEmpty()) {
            sb.append("order by ").append(orderStr);
        } else {
            sb.append("order by ").append(orderStr).append(" ").append(others);
        }

        if (groupQueryStr != null) {
            sb.append("| ").append(groupQueryStr);
        }

        return sb.toString();
    }
Order by desc.
https://docs.vespa.ai/en/reference/query-language-reference.html#order-by

@param fieldName the field name
@return the end query
client/src/main/java/ai/vespa/client/dsl/EndQuery.java