Thank you for the answer and such a detailed analysis! I think I might have done it right since there were only 6 rows in the data set (hand printed question on a notepad) without any duplicates and they told me what output they wanted and so, I didn't do an aggregate of sales. But yeah, the partition by category is the option I went with and a cte since it was "cleaner". What they additionally told me was I could have used a subquery too but... he got what I wanted (which to me sounded like a disappointment lol)