yea my solution works but its f-kin brain dead

This question is amazing! i think i finally understood the difference b/w order and partition. But i could forget everything tomorrow morning.

i think this is the best solution so far. i almost did the same thing but ended up doing a join for total_quantity_on_max_day for no reason lol

what is the problem that you are reporting exactly ? is there something wrong with the kata ?

just keep in mind that producent coulmns can contain values like "CompanyA", "CompanyB" etc which u might want to use in your solution