Grouping using two criteria / subgroups / subtotals
I have a dataset that works a bit like my first picture here:
What I need is an output that looks something like this:
By that, I mean that I don't simply want a total of how many drinks were sold overall by each person, or how many of each drink were sold (which I could do with the group function in Magic ETL). I need to group according to the two criteria.
Can anyone suggest what I'd have to do in Magic ETL to achieve this?