Multi-column grouping

Group by multiple columns.

Grouping by multiple columns creates subgroups. Column order matters.

SELECT country, city, COUNT(*)
FROM customers
GROUP BY country, city;

This query counts by country and city.

country, city, COUNT(*) is selected from customers. Rows are grouped by country, city; aggregate functions are computed per group.

Multi-column grouping — details

The first column is the parent group, the second is the subgroup. Each distinct pair is a row.

For example, GROUP BY country, city gives a separate row for each city in each country: Türkiye-İzmir and Türkiye-Bursa are separate groups.

Group customers first by country then by city.

Show example solution

SELECT country, city, COUNT(*)
FROM customers
GROUP BY country, city;

Add the second column

SELECT country, city, COUNT(*)
FROM customers
GROUP BY country, ____;

Show answer

SELECT country, city, COUNT(*)
FROM customers
GROUP BY country, city;