It's useful to put the grouping columns so you can say `group by 1,2,3,4,5` instead of `group by 1,2,6,7,9`. Implementing production queries, you tend to writ

It's useful to put the grouping columns so you can say `group by 1,2,3,4,5` instead of `group by 1,2,6,7,9`. Implementing production queries, you tend to write out the full column names, but for 95% of your SQL this is a boon to the analyst or data scientist.