第一题SQL....你们的看着好难.... select sku_name, ss.category, ss.qty from (select si.sku_name, si.category, sum(s.qty) as 'qty' from sku_info si left join sales s on si.sku_no = s.sku_no group by si.sku_name, si.category order by qty DESC) ss join (select max(sncq.qty) as 'qty', category from (select si.category, sum(s.qty) as 'qty' from sku_info si left join sales s on si.sku_no = s.sku_no group by si.sku_name, si.category) as sncq group by category) sss where ss.category = sss.category and ss.qty = sss.qty;