Totals that include empty groups in SQL
SQL interview exercise on Joins, difficulty 2 of 3. Solve it in the editor beside a worked example, or cold in Interview mode with the example hidden; the tests run the moment you do.
Return every department with its headcount and total salary. A department with no employees shows 0 for both, not NULL. Columns: department, headcount, total_salary. Sorted by department.
Each exercise pairs a worked example with a twin problem to solve in a real editor; the tests run the moment you do. Interview mode hides the example: solve it from memory, without the hint or the solution, and it counts as solved cold. Progress is saved in your browser, and in your account if you sign in.