Question

Hey so I have a stored procedure populating a gridview

and in my stored procedure I have two columns such as

Total_Price DataType Money

and

Discount DateType decimal(18, 0)

and I want to display a derived column called Actual Price which is

Total_Price - Discount

is it best to create this column in the stored procedure or calculate on load in the gridview ?

Heres my stored procedure at the moment

    SELECT     f.supplier_name,d.product_ID_key, d.product_name AS productName, d.packsize, d.tradePrice, d.IPU_code, d.EAN_code, c.discount, e.stock_indicator
FROM         aw_customer AS a INNER JOIN
                      aw_cust_contract AS b ON a.cust_ID_key = b.cust_ID_key INNER JOIN
                      aw_contract_line AS c ON b.contract_ID_key = c.contract_ID_key INNER JOIN
                      aw_product AS d ON c.product_ID_key = d.product_ID_key INNER JOIN
                      aw_stock AS e ON d.product_ID_key = e.product_ID_key INNER JOIN
                      aw_supplier AS f ON d.supplier_ID_key = f.supplier_ID_key
WHERE     (a.cust_ID_key = @customerId)
ORDER BY d.product_name

Answer 1

I would calculate this at Stored Procedure level, so that any calls to this Stored Procedure would return the same results (you haven’t got to do the math on other gridviews etc in the future if they are calling the same Stored Procedure)

In situations like this, I’ve often created a SQL View so that the calculations are done within the view, and then multiple Stored Procedures can call this View and display the data like:

SELECT Total_Price
       ,Discount
       ,Actual_Price
FROM [v_TableA]

http://msdn.microsoft.com/en-us/library/aa214068%28v=sql.80%29.aspx

See this article for details of Indexing Views, which will also improve performance:

http://technet.microsoft.com/en-us/library/cc917715.aspx