👀 Задачка по нашей базе данных, которая находится в шапке канала. Код генерации базы данных и INSERT данных по ссылке ТУТ. ВОПРОС: Какой запрос вернёт клиентов, которые не сделали ни одного заказа?
1. SELECT * FROM order_table WHERE customer_id IS NULL;
2. SELECT * FROM customer EXCEPT SELECT * FROM order_table;
3. SELECT * FROM customer c LEFT JOIN order_table o ON c.customer_id = o.customer_id WHERE o.order_id IS NULL;
4. SELECT * FROM customer WHERE order_id IS NULL;
Правильный ответ 👇
SELECT * FROM customer c LEFT JOIN order_table o ON c.customer_id = o.customer_id WHERE o.order_id IS NULL;
Если вам понравился вопрос - зашарьте его друзьям👉SQLQuestions
👀 Задачка по нашей базе данных, которая находится в шапке канала. Код генерации базы данных и INSERT данных по ссылке ТУТ. ВОПРОС: Какой запрос вернёт клиентов, которые не сделали ни одного заказа?
1. SELECT * FROM order_table WHERE customer_id IS NULL;
2. SELECT * FROM customer EXCEPT SELECT * FROM order_table;
3. SELECT * FROM customer c LEFT JOIN order_table o ON c.customer_id = o.customer_id WHERE o.order_id IS NULL;
4. SELECT * FROM customer WHERE order_id IS NULL;
Правильный ответ 👇
SELECT * FROM customer c LEFT JOIN order_table o ON c.customer_id = o.customer_id WHERE o.order_id IS NULL;
Если вам понравился вопрос - зашарьте его друзьям👉SQLQuestions
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