-- Database schema
| Customers : CustomerID [ INTEGER ] primary_key , FirstName [ TEXT ] , MiddleInitial [ TEXT ] , LastName [ TEXT ] | Employees : EmployeeID [ INTEGER ] primary_key , FirstName [ TEXT ] , MiddleInitial [ TEXT ] , LastName [ TEXT ] | Products : ProductID [ INTEGER ] primary_key , Name [ TEXT ] , Price [ REAL ] | Sales : SalesID [ INTEGER ] primary_key , SalesPersonID [ INTEGER ] Sales.SalesPersonID = Employees.EmployeeID , CustomerID [ INTEGER ] Sales.CustomerID = Customers.CustomerID , ProductID [ INTEGER ] Sales.ProductID = Products.ProductID , Quantity [ INTEGER ] |
-- -- Name the sales person who helped Elizabeth A. White to purchase Road-250 Black, 48.

SELECT DISTINCT T3.FirstName, T3.MiddleInitial, T3.LastName FROM Products AS T1 INNER JOIN Sales AS T2 ON T1.ProductID = T2.ProductID INNER JOIN Employees AS T3 ON T2.SalesPersonID = T3.EmployeeID INNER JOIN Customers AS T4 ON T2.CustomerID = T4.CustomerID WHERE T4.MiddleInitial = 'A' AND T4.LastName = 'White' AND T1.Name = 'Road-250 Black, 48' AND T4.FirstName = 'Elizabeth';