将SQL中的行与特定逻辑合并

您可以使用 案例外部参照 具有 group by

select v.ProductCategory, Sum(qty) Qty, Sum(price) Price
from t
cross apply (values(
    case when productcategory in ('Misc','Extra') then 'Other' /*or Extra...?*/
    else ProductCategory 
  end)
)v(ProductCategory)
group by v.ProductCategory

Example fiddle

对临时表使用OUTPUT

declare @tmp table(Qty int, Price int);

delete tbl
  output deleted.qty, deleted.price into @tmp (Qty, Price)
where ProductCategory in ('Misc','Other');

update t
  set Qty = t.Qty + u.qty , Price = t.Price + u.Price
from tbl t
join (select sum(Qty) qty, sum(Price) Price
      from @tmp) u
      on t.ProductCategory = 'Extra';

db<>fiddle