The Manager Pay Gap

A fairness audit at Kestrel Labs is checking for compressed reporting lines — cases in which somebody is paid nearly as much as the person they report to. It is a standard red flag: it usually means a report has been kept at market rate while their manager's salary has sat still, and the next raise will invert the two.

The audit wants the three tightest cases to look at first. The obstacle is that a person and their manager are both employee rows, and a row only holds a number pointing at the other one.

employees — one row per person. department_id is the team they sit on, given as the matching id in departments; salary is annual pay in dollars; hire_date is the day they started, written year-month-day; manager_id is the id of the person they report to, and is NULL for anyone who reports to nobody.

The table already exists in the database — there is nothing to create or load.

Task: Write a query returning three columns, employee (the report's name), manager (their manager's name) and gap (the manager's salary minus the employee's salary), returning only the three tightest cases, smallest gap first. Only people who have a manager recorded can appear. A negative gap would mean somebody out-earns their manager and should sort to the very top; there are none in this data, and the third and fourth tightest gaps are 2000 apart, so the three rows are not in doubt.

Example output — shape only, on invented pairs. The top row is the case the task warns about: a negative gap means the report out-earns the manager, and it sorts above every positive one: