Sum of rows in SQL with GROUP BY

Question

I am having a table with data like:

ID  OrderId TAX%    Quantity UnitCost
1     5      28    2       1280
2     5      18    1       1180

I want the output like:

ORDERID    TaxableValue       TaxValue
   5           3000               740

How can I achieve this? I tried with:

SELECT orderid,
       ROUND((SUM(UnitCost*Quantity)*TAX)/(100+TAX),2) AS taxValue,
       ROUND(SUM(unitCost*quantity)-ROUND((SUM(UnitCost*Quantity)*TAX)/(100+TAX),2),2) AS taxableValue 
FROM table1 
GROUP BY OrderId;

But the query above is not working.

Sorry all, That is the Tax percentage. This is the new Updated Query. Please consider this.

Answer 1

Pretty sure it is as simple as doing a little math.

select OrderID
    , TaxableValue = SUM(UnitCost - TAX)
    , TaxValue = SUM(TAX * Quantity)
from YourTable
group by OrderID

EDIT: The math was slightly off on the TaxableValue

For those who want proof that this works.

declare @Something table
(
    ID int
    , OrderId int
    , TAX int
    , Quantity int
    , UnitCost int
)

insert @Something values
(1, 5, 28, 2, 228)
, (2, 5, 18, 1, 118)

select OrderID
    , TaxableValue = SUM(UnitCost - TAX)
    , TaxValue = SUM(TAX * Quantity)
from @Something
group by OrderID

Answer 2

This is how it can be done.

SELECT 
orderid, 
sum(unitcost*quantity) - sum(tax*quantity) as taxablevalue,
sum(tax*quantity) as taxvalue
FROM table1  
GROUP BY OrderId;

Answer 3

select OrderId
    , SUM((unitcost * quantity * tax)/(100+tax)) as TaxValue
    , SUM(unitcost * quantity)-SUM((unitcost * quantity * tax)/(100+tax)) as taxableValue
from table1
group by OrderId