Stored Procedure Select from 3 tables - sql

Question

I have three tables in my database Sales, SalesPeople and Appliances.
Sales
SaleDate EmployeeID AppID Qty
---------- ---------- ----- -----------
2010-01-01 1412 150 1
2010-01-05 3231 110 1
2010-01-03 2920 110 2
2010-01-13 1412 100 1
2010-01-25 1235 150 2
2010-01-22 1235 100 2
2010-01-12 2920 150 3
2010-01-14 3231 100 1
2010-01-15 1235 300 1
2010-01-03 2920 200 2
2010-01-31 2920 310 1
2010-01-05 1412 420 1
2010-01-15 3231 400 2
SalesPeople
EmployeeID EmployeeName CommRate BaseSalary SupervisorID
---------- ------------------------------ ----------- ----------- ------------
1235 Linda Smith 15 1200 1412
1412 Anne Green 12 1800 NULL
2920 Charles Brown 10 1150 1412
3231 Harry Purple 18 1700 1412
Appliances
ID AppType StoreID Cost Price
---- -------------------- ------- ------------- -------------
100 Refrigerator 22 150 250
110 Refrigerator 20 175 300
150 Television 27 225 340
200 Microwave Oven 22 120 180
300 Washer 27 200 325
310 Washer 22 280 400
400 Dryer 20 150 220
420 Dryer 22 240 360
How can I obtain this result? (That displays the profitability of each of the salespeople ordered from the most profitable to the least. Gross is simply the sum of the quantity of items sold multiplied by the price. Commission is calculated from the gross minus the cost of those items (i.e. from
qty*(price-cost)). Net profit is the total profit minus commission.)
Name Gross Commission Net Profit
------------- ----- ---------- ---------
Charles Brown 2380 83.5 751.5
Linda Smith 1505 83.25 471.75
Harry Purple 990 65.7 299.3
Anne Green 950 40.2 294.8
My attempt:
CREATE PROC Profitability AS
SELECT
sp.EmployeeName, (sum(s.Qty) * a.Price) as [Gross],
[Gross] - a.Cost, as [Commision],
SOMETHING as [Net Profit]
FROM
Salespeople sp, Appliances a, Sales s
WHERE
s.AppID = a.ID
AND sp.EmployeeID = s.EmployeeID
GROUP BY
sp.EmployeeName
GO
EXEC Profitability

Answer 1

Simple rule: Never use commas in the FROM clause. Always use explicit JOIN syntax.
In addition to fixing the JOIN syntax, your query needs a few other enhancements for the aggregation functions:
SELECT sp.EmployeeName, sum(s.Qty * a.Price) as Gross,
SUM(s.Qty * (a.Price - a.Cost)) * sp.CommRate / 100.0 as Commission,
SUM(s.Qty * (a.Price - a.Cost)) * (1 - sp.CommRate / 100.0) as NetProfit
FROM Sales s JOIN
Salespeople sp
ON sp.EmployeeID = s.EmployeeID JOIN
Appliances a
ON s.AppID = a.ID
GROUP BY sp.EmployeeName sp.CommRate
ORDER BY NetProfit DESC;