In SQL Server, the GROUPING SETS clause allows you to generate multiple grouping sets within a single query. It provides a way to specify multiple grouping criteria and compute aggregates for each group.

To use GROUPING SETS to generate multiple grouping sets, follow these steps:

1. Start with a basic SELECT statement that includes the columns you want to group by and the aggregate functions you want to apply. For example:

<span class="hljs-keyword">SELECT</span> column1, column2, <span class="hljs-built_in">SUM</span>(sales) <span class="hljs-keyword">AS</span> total_sales
<span class="hljs-keyword">FROM</span> your_table
<span class="hljs-keyword">GROUP</span> <span class="hljs-keyword">BY</span> column1, column2;


1. Modify the GROUP BY clause to include the GROUPING SETS keyword and specify the grouping sets you want to generate. Each grouping set is enclosed in parentheses and contains the columns you want to group by. For example, to generate grouping sets for column1, column2, and both columns together, you can use the following query:

<span class="hljs-keyword">SELECT</span> column1, column2, <span class="hljs-built_in">SUM</span>(sales) <span class="hljs-keyword">AS</span> total_sales
<span class="hljs-keyword">FROM</span> your_table
<span class="hljs-keyword">GROUP</span> <span class="hljs-keyword">BY</span> <span class="hljs-keyword">GROUPING</span> SETS (
(column1),
(column2),
(column1, column2)
);


In this example, three grouping sets are defined: one for column1, one for column2, and one for both column1 and column2.

1. Execute the query, and SQL Server will compute the aggregates for each grouping set. The result will include the specified columns and the calculated aggregates.

Note: When using GROUPING SETS, NULL values will be used to represent the columns that are not included in a particular grouping set.

By utilizing the GROUPING SETS clause, you can efficiently generate multiple grouping sets within a single query and obtain aggregated results based on each grouping criteria.