Subquery with IN

Use a subquery inside IN.

With IN a subquery returns a list. The outer query searches for values in that list.

SELECT name FROM customers
WHERE id IN (SELECT customer_id FROM orders);

This query returns customers who placed orders.

name is selected from customers. WHERE keeps only the rows where id IN (SELECT customer_id FROM orders) holds.

Subquery with IN — details

An IN subquery can return many rows. Each value is looked up in the outer query.

For example, WHERE id IN (SELECT customer_id FROM orders) returns customers with at least one order.

Find customers who ordered using IN (SELECT customer_id FROM orders).

Show example solution

SELECT name FROM customers
WHERE id IN (SELECT customer_id FROM orders);

Add IN

SELECT name FROM customers
WHERE id ____ (SELECT customer_id FROM orders);

Show answer

SELECT name FROM customers
WHERE id IN (SELECT customer_id FROM orders);

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