SQL interview question: SAVEPOINT and ROLLBACK TO
The Reversible Experiment
Finance (department_id 5) gets a confirmed $1,000 raise per person. While you're in there, an analyst wants to trial-run doubling every salary - but that experiment must NOT survive.
Write one transaction that: applies the Finance raise, opens a SAVEPOINT named experiment, doubles every salary, rolls back to the savepoint, and COMMITs. Only the Finance raise should remain.
Note: Multiple statements allowed. Runs on a scratch copy and is discarded afterwards.
Tables
employees 37 rows
- id integer PK
- first_name text
- last_name text
- email text
- department_id integer → departments
- salary integer
- hire_date text
- manager_id integer → employees
- title text
| id | first_name | last_name | department_id | salary | hire_date | manager_id | title | |
|---|---|---|---|---|---|---|---|---|
| 1 | Alice | Chen | [email protected] | 1 | 250000 | 2015-01-15 | NULL | CEO |
| 2 | Robert | Martinez | [email protected] | 2 | 180000 | 2016-03-20 | NULL | CEO |
| 3 | Sarah | Johnson | [email protected] | 1 | 150000 | 2017-06-10 | 1 | VP Engineering |