QuerydrillCustomers per country
An SQL exercise from Querydrill. Solve it with a SQL editor in your browser, checked on the rows it returns and again on changed data, and it is checked the moment you submit.
The task
For each country, return the country and how many customers it has.
What this exercise teaches
GROUP BY splits the rows into buckets, and the aggregate runs once per bucket.
A hint if you get stuck
Every column in SELECT that is not an aggregate must appear in GROUP BY.
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