Show me all the information from invoices!
select * from invoices
What is the country with the least number of invoices?
select billing_country, count(*) from invoices group by billing_country order by count(*) asc limit 1;
How about the one with the most!
select billing_country, count(*) from invoices group by billing_country order by count(*) desc limit 1;
How about the top 5?
select billing_country, count(*) from invoices group by billing_country order by count(*) desc limit 5;