Oracle Sql 开发人员（选择计数） Twoc 列

Question

I have to make a query that has the Total number of customers by country and city

country and city are columns that are inside the customer table

On my own I have managed to get the total number of customers per city like this:

SELECT city, COUNT (*)
FROM employees
GROUP BY city
ORDER BY city

But how do I get it together with the country? looking for information I think it should be something like this and ordered from largest to smallest

Country	City	TOTAL_CUSTOMERS
USA	Kirkland	3
USA	London	2
UK	Redmond	2
UK	Seattle	1
UK	Tacoma	1

What we have been told is to say Total number of customers by country and city.

Answer 1

You simply add country to the column list and group by list:

SELECT country,city, COUNT(*)
FROM employees
GROUP BY country,city
ORDER BY COUNT(*) DESC