Summary - EXISTS

Find customers with no orders using NOT EXISTS.

EXISTS checks whether a subquery returns rows. NOT EXISTS finds missing records.

SELECT name FROM customers c
WHERE NOT EXISTS (SELECT 1 FROM orders o WHERE o.customer_id = c.id);

Summary EXISTS query.

name is selected from customers c. WHERE keeps only the rows where NOT EXISTS (SELECT 1 FROM orders o WHERE o.customer_id = … holds.

Exercise Summary - EXISTS

Summary: find customers without orders using NOT EXISTS.

Show example solution

SELECT name FROM customers c
WHERE NOT EXISTS (SELECT 1 FROM orders o WHERE o.customer_id = c.id);

Next lesson: UNION