Case study stored procedures

Writing Functions and Stored Procedures in SQL Server

Meghan Kwartler

IT Consultant

Taxi ride business problem

EU private equity firm seeking investment opportunity in US Transportation.
What is the average fare per distance, ride count & total ride time for each NYC borough on each day of the week?
Which pickup locations within the borough should be scheduled for each of the driver shifts?

Evolution of an SP

--Query detail level with UDFs
SELECT 
  DATENAME (weekday, PickupDate) as 'Weekday', 
  PickupDate, 
  DropOffDate, 
  TotalAmount, 
  TripDistance, 
  dbo.ConvertDollar(TotalAmount,.88)/ dbo.ConvertMileToKm(TripDistance) as 'EuroFarePerKM', 
  DATEDIFF(SECOND, PickupDate, DropOffDate)/ 60 as 'TotalRideMin' 
FROM YellowTripData 
WHERE TripDistance > 0

SELECT DATENAME(weekday, PickupDate) as 'Weekday', 
     Zone.Borough as 'PickupBorough',
     AVG(dbo.ConvertDollar(TotalAmount, .77)/
     dbo.ConvertMiletoKM(TripDistance)))
     AS 'AvgFarePerKM',
     COUNT (ID) as 'RideCount',
     SUM(DATEDIFF(SECOND, PickupDate, DropOffDate)/60) as 'TotalRideMin'
FROM YellowTripData
INNER JOIN TaxiZoneLookup AS Zone 
ON PULocationID = Zone.LocationID 
WHERE dbo.ConvertMiletoKM(TripDistance) > 0 
GROUP BY DATENAME(WEEKDAY, PickupDate), Zone.Borough
ORDER BY CASE
          WHEN DATENAME(WEEKDAY, PickupDate) = 'Monday' THEN 1
          WHEN DATENAME(WEEKDAY, PickupDate) = 'Tuesday' THEN 2
          WHEN DATENAME(WEEKDAY, PickupDate) = 'Wednesday' THEN 3
          WHEN DATENAME(WEEKDAY, PickupDate) = 'Thursday' THEN 4
          WHEN DATENAME(WEEKDAY, PickupDate) = 'Friday' THEN 5
          WHEN DATENAME(WEEKDAY, PickupDate) = 'Saturday' THEN 6
          WHEN DATENAME(WEEKDAY, PickupDate) = 'Sunday' THEN 7
        END,  
AVG(dbo.ConvertDollar(TotalAmount, .77)/dbo.ConvertMiletoKM(TripDistance)) DESC;

"Last" step

CREATE OR ALTER PROCEDURE dbo.cuspPickupZoneShiftStats
@Borough nvarchar(30)
AS
BEGIN
.....
END

DROP PROCEDURE IF EXISTS dbo.cuspPickupZoneShiftStats
GO
CREATE PROCEDURE dbo.cuspPickupZoneShiftStats
@Borough nvarchar(30)
AS
BEGIN
....
END

Your turn!

Writing Functions and Stored Procedures in SQL Server