SQL is the dominant technology for accessing application data. It is increasingly becoming a performance bottleneck when it comes to scalability. Given its dominance, SQL is a crucial skill for all engineers.
Subqueries are commonly used in database interactions, making it important for a programmer to be skilled at writing them.
Public questions (free account) are common interview questions. They are great for practicing, or if you want to filter candidates using the classic problems.
Given the following data definition, write a query that selects the names of employees that are not managers.
TABLE employees id INTEGER NOT NULL PRIMARY KEY managerId INTEGER REFERENCES employees(id) name VARCHAR(30) NOT NULL
See the example case for more details.
- Example case: Wrong answer
- No managers: Wrong answer
- Workers have managers: Wrong answer
- Managers have managers: Wrong answer