Join a table to itself in SQL
SQL interview exercise on Joins, difficulty 2 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 every employee with their manager's name. The CEO has no manager and still appears, with NULL. Columns: employee, manager. Sorted by 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.