Correlated subquery: latest per group in SQL
SQL interview exercise on Subqueries & CTEs, difficulty 3 of 3. Solve it in the editor beside a worked example; the tests run the moment you do.
Return each customer's most recent order. Customers without orders do not appear. Columns: customer, order_id, ordered_on. Sorted by customer.
Each exercise pairs a worked example with a twin problem to solve in a real editor; the tests run the moment you do. Progress is saved in your browser, and in your account if you sign in.