Who Reports to No One?

The org-chart tool at Kestrel Labs draws a line from each person up to whoever they report to, and this morning it crashed. The cause turned out to be the people at the top: they report to nobody, so the field holding their manager is empty rather than pointing anywhere, and the tool tried to draw a line to nothing.

Before the fix ships, the engineer wants the list of exactly who those people are, so she can eyeball it against the real leadership team. Alphabetical, because she is reading it against a printed org chart.

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 a single column, name, listing every employee who has no manager recorded — that is, whose manager_id is NULL rather than pointing at another employee's id. Sort the rows alphabetically by name, ascending. All four names are different, so that fixes the order exactly.

Example output — shape only, on invented people. If three records had an empty manager slot, you would get: