Employees With No Manager
Kestrel Labs is tidying its org chart before a compliance audit. Every employee row has a manager_id pointing at the row of the person they report to — except that some rows have nothing in that column at all. A few of those people genuinely report to nobody; others are gaps somebody never filled in. The auditor wants all of them on one list either way, so a human can go and ask which is which.
Worth knowing before you start: an absent value in SQL is not a zero and not an empty string. It is NULL, and NULL plays by its own comparison rules — it is never considered equal to anything, not even to another NULL.
employees — one row per employee. manager_id holds the id of that person's manager, or NULL if none is recorded.
| id | name | department_id | salary | hire_date | manager_id |
|---|---|---|---|---|---|
| 1 | Ava Chen | 1 | 145000 | 2021-03-14 | NULL |
| 2 | Ben Ortiz | 1 | 118000 | 2022-06-01 | 1 |
| 3 | Cara Novak | 1 | 121000 | 2023-01-10 | 1 |
| 4 | Deshawn Lee | 2 | 95000 | 2020-09-23 | NULL |
| 5 | Elin Kask | 2 | 88000 | 2022-11-05 | 4 |
| 6 | Farid Amiri | 3 | 76000 | 2023-04-18 | NULL |
| 7 | Grace Kim | 4 | 132000 | 2021-07-30 | NULL |
| 8 | Hugo Silva | 4 | 110000 | 2023-02-14 | 7 |
| 9 | Ines Duarte | 4 | 104000 | 2023-08-01 | 7 |
| 10 | Jonas Weber | 2 | 91000 | 2021-12-19 | 4 |
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 with no manager recorded, sorted alphabetically by name.
Example output — shape only, on invented names.
| name |
|---|
| Anton Reis |
| Rosa Kwan |
| Yusuf Bello |
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