What is the current payrate of Rob Walters? Calculate the percentage increment from his previous payrate.
current payrate refers to max(Rate); percentage increment = divide(subtract(max(Rate), min(Rate)), min(Rate))*100%
SELECT T2.Rate , (MAX(T2.Rate) - MIN(T2.Rate)) * 100 / MAX(T2.Rate) FROM Person AS T1 INNER JOIN EmployeePayHistory AS T2 ON T1.BusinessEntityID = T2.BusinessEntityID WHERE T1.FirstName = 'Rob' AND T1.LastName = 'Walters'