What does GROUP BY ROLLUP(dept, role) produce compared to a plain GROUP BY?

Question

SQL Data Analyst — Medium

What does GROUP BY ROLLUP(dept, role) produce compared to a plain GROUP BY?

Accepted Answer

GROUP BY ROLLUP(dept, role) produces subtotals per dept, a grand total across all depts, and detail-level dept/role aggregates in a single query. This allows for a comprehensive analysis of data at different levels of granularity.