What does the following query return? SELECT department, COUNT(*) FROM employees GROUP BY GROUPING SETS ((department), ())

Question

SQL Fundamentals — Hard

What does the following query return? SELECT department, COUNT(*) FROM employees GROUP BY GROUPING SETS ((department), ())

Accepted Answer

This query with GROUPING SETS returns per-department row counts along with a grand total row. It groups by department and also includes an empty grouping set for the grand total.