如何在不使用sum函数的情况下对sum进行分组？

Question

There's a customer table having id, firstname, country and invoice total( for each customer). I need to write a query displaying list of countries (in descending order) according to revenue generated by each country. I'm trying the following the following query:

Select country, sum(invoicetotal) from customer group by country order by 2 desc

The output is according to the expected result but with an additional column of sum(invoicetotal). I cannot figure a way to order the countries according to the sum of their imvoicetotal without using sum() function in select.

Answer 1

You should be able to do:

select country
from t
group by country
order by sum(revenue) desc;

I think all databases support the use of aggregation functions in the order by even if the value is not in the select .