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RED SAGSkills
medium10 pts · first answer countssqljoinsaggregation

Counting orders for every customer

customers A, B, C. orders: A has 2, B has 1, C has none. The query groups a LEFT JOIN by customer. What does it show for C in each column?

SELECT c.name, COUNT(*) AS a, COUNT(o.id) AS b
FROM customers c
LEFT JOIN orders o ON o.customer_id = c.id
GROUP BY c.name;
Choose one answer