GROUP BY中的SQL计数行

Question

The following query returns the following results:

SELECT sales.users_id, users.region
FROM sales
JOIN users ON ( sales.users_id = users.id )
GROUP BY sales.users_id

users_id, region
1,    IE
2,    UK
3,    UK
4,    UK
5,    AU
6,    AU

QUESTION:

How do I modify the above query to get the following results:

IE, 1
UK, 3
AU, 2

Which is the number of users who purchased per region. Where the numbers in the second column correspond to the count of sales per region?

Thanks in advance...

Answer 1

SELECT users.region, count(*)
FROM sales
JOIN users ON ( sales.users_id = users.id )
GROUP BY users.region;