-- 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 ] |
-- -- What is the difference in price between HL Mountain Frame - Black, 42 and LL Mountain Frame - Black, 42?

SELECT ( SELECT Price FROM Products WHERE Name = 'HL Mountain Frame - Black, 42' ) - ( SELECT Price FROM Products WHERE Name = 'LL Mountain Frame - Black, 42' ) AS num;