On: The Next 50 Years of Databases (2015)

[paulddraper]

You virtually always want this.

   SELECT count(*), favorite_color, favorite_song
   FROM person
   GROUP BY ...

The "..." is of course favorite_color, favorite_song.

Whether you want this or not, ANSI SQL requires that you group by at least these.

You could group by more more fields, such as favorite_pet, though that would be somewhat odd since you are did not include it in the result set.

[jimktrains2 → paulddraper]

Ah, you meant in the select, not the table. I guess I'm just much more in favour of being explicit, but I can understand the usefulness of what you said now that I fully understand it.