Top N per group with ROW_NUMBER in SQL
SQL interview exercise on Window Functions, difficulty 3 of 3. Solve it in the editor beside a worked example, or cold in Interview mode with the example hidden; the tests run the moment you do.
Return the two highest-paid employees of each department (employees without a department are left out). Break salary ties by name, so exactly two rows come back per department that has at least two people. Columns: department, employee, salary. Sorted by department, then salary descending, then employee.
Each exercise pairs a worked example with a twin problem to solve in a real editor; the tests run the moment you do. Interview mode hides the example: solve it from memory, without the hint or the solution, and it counts as solved cold. Progress is saved in your browser, and in your account if you sign in.