在SQL查询中，如何获取另一个和的和？

我不知道如何求另一个数的和。所有的钥匙都是正确的。如果我像这样去掉第一笔金额， 选择b.BranchName、SUMob.FirstQty+ob.SecondQty*ps.Price TotalCost 它正在工作，但它显示了多个成本，如100、200、300等。我想要的是这些多个成本的总成本。

从GROUP BY子句中删除ps.Price，并在sum函数中使用一对额外的括号与Price相乘

查询变成这样：

SELECT b.BranchName, SUM(SUM(ob.FirstQty + ob.SecondQty))* ps.Price TotalCost
FROM Branch b, Product_Supplier ps, Product p, Supplier s, Order o, Order_Details od
WHERE o.BranchID = b.BranchID
AND o.OrderID = ob.OrderID
AND ob.ProductID = p.ProductID
AND p.FirstSupplierID = s.SupplierID
AND ps.SupplierID = s.SupplierID
AND ps.ProductID = ob.ProductID
AND b.BranchID = 1
AND o.OrderDate >= '2015-01-09'
AND o.OrderDate <= '2015-09-09'
Group By b.BranchName, ps.Price

SELECT b.BranchName, SUM((ob.FirstQty + ob.SecondQty) * ps.Price) TotalCost
FROM Branch b, Product_Supplier ps, Product p, Supplier s, Order o, Order_Details od
WHERE o.BranchID = b.BranchID
AND o.OrderID = ob.OrderID
AND ob.ProductID = p.ProductID
AND p.FirstSupplierID = s.SupplierID
AND ps.SupplierID = s.SupplierID
AND ps.ProductID = ob.ProductID
AND b.BranchID = 1
AND o.OrderDate >= '2015-01-09'
AND o.OrderDate <= '2015-09-09'
Group By b.BranchName