Stored procedure and print output

Question

Based on my previous question, I'm trying to print various columns from different tables and only print the top 10 most profitable products and it is calculated by sellingprice - costprice. How can I print out the top 10 output line by line like its on a table?

CREATE PROCEDURE usp_top10ProfitableProducts
     @productID int Output,
     @productdes VARCHAR(100) Output,
     @quantityorder int Output,
     @totalProfit DECIMAL(5,2) Output
AS
BEGIN
    SELECT Top 10 * 
    FROM
        (SELECT 
             @productID = productID, 
             @productdes = Product.description, 
             @quantityorder = CustomerInventory.quantityOrdered, @totalProfit = (Inventory.sellingPrice-Inventory.costPrice) AS difference
         FROM 
             Product p, Supplier s, SupplierOrder so, Inventory in, CustomerInventory cin
         WHERE 
             p.ProductID = s.productID, s.supplierID = so.supplierID, so.supOrderID = in.supOrderID, in.barcodeNo = cin.barcodeNo) difference_data
    ORDER BY 
       difference DESC

    DECLARE @productID INT
    DECLARE @productdes VARCHAR(100)
    DECLARE @quantityorder INT
    DECLARE @totalProfit DECIMAL(5,2)

    EXECUTE usp_top10ProfitableProducts
        @productID OUT
        @productdes OUT
        @quantityORDER OUT
        @totalProfit OUT

    PRINT

Answer 1

Instead of a procedure, use a view. However, there are other things to fix:

• Never use commas in the FROM clause. Always use explicit JOIN syntax.
• Qualifying column names is good, but you need to use the table alias rather than the column name

The view looks like:

CREATE VIEW vw_top10ProfitableProducts as
    SELECT Top 10 p.productID, p.description, ci.quantityOrdered,
           (i.sellingPrice - i.costPrice) as Difference 
    FROM Product p JOIN
         Supplier s
         ON p.ProductID = s.productID JOIN
         SupplierOrder so
         ON s.supplierID = so.supplierID JOIN
         Inventory in
         ON so.supOrderID = in.supOrderID JOIN
         CustomerInventory cin
         ON in.barcodeNo = cin.barcodeNo
    ORDER BY difference Desc;

You can then access it just like a regular table:

select *
from vw_top10ProfitableProducts;

This is much easier than using stored procedures. In any case, your stored procedure could never work, because you want to return ten rows, but you have only four output parameters.