• I confess I'd have struggled to actually work these out in any way so apologise for 'cheating' (I ran it on my desktop instance) although I think learning about grouping sets was worthwhile.

    I'd like anyone's advice about when this might be a useful technique to use? I'd admit that in this instance the result set seemed confusing to me and I'd never put something like that in front of (my) clients. If I needed all those bits of data to display as a single presentation, say for a dashboard, I'd probably find writing separate queries less confusing to write and maintain.