Detailed T-SQL GROUP by GROUPING SETS

Recently encountered a situation, need to be in the intranet system a statistical report. You need to use multiple group by statements based on different criteria. All aggregated data needs to be union to perform statistical viewing of different dimensions.

Until the discovery of the introduction of grouping SETS after SQL SERVER 2008, which is a much simpler requirement for group BY, let me explain grouping SETS using the table in Adventurework as a demo.

Suppose I now need two dimensions to query my sales order, and query T-SQL is as follows:

And with the new grouping sets statement after SQL SERVER 2008, you just need to write this:

It is noteworthy that although the results from the above grouping sets statement and multiple group by statements are identical, the order is completely different.

GROUPING SETS, just a grammar candy?