What does the GROUPING() function return when used with ROLLUP or CUBE?

Question

SQL Data Analyst — Medium

What does the GROUPING() function return when used with ROLLUP or CUBE?

Accepted Answer

The GROUPING() function returns 1 if the column value is NULL due to rollup aggregation, and 0 if it is an actual group value. This helps differentiate between the aggregated NULL values and actual group values.