Add GROUPING SETS Support to GROUP BY Clause with Parallel Processing

Why it matters

This feature addresses the need for more flexible and efficient aggregation by allowing users to specify multiple grouping sets in a single query. It improves query performance and simplifies complex aggregation queries by processing grouping sets in parallel.

How to use it

Users can include GROUPING SETS within the GROUP BY clause in their SQL queries like this:

SELECT <columns>, <aggregates>
FROM <table>
GROUP BY GROUPING SETS ((<grouping_set1>), (<grouping_set2>), ...)

This syntax activates the feature and benefits from optimized parallel processing of grouping sets.