Lección 8 de 9
GROUP BY y agregados
GROUP BY agrupa filas con los mismos valores. Usa funciones agregadas como COUNT(), SUM(), AVG(), MAX() y MIN() para calcular valores por grupo.
SQL
-- Count users per country
SELECT country, COUNT(*) as total_users
FROM users
GROUP BY country;
-- Average price per category
SELECT category, AVG(price) as avg_price
FROM products
GROUP BY category;
-- Having filters groups (like WHERE for groups)
SELECT country, COUNT(*) as total
FROM users
GROUP BY country
HAVING total > 10;