In a vehicle servicing database, customers can be ranked according to the total amount of money they have spent on servicing their vehicles. This type of query is useful for identifying high-value customers and understanding customer expenditure patterns. In a DBMS and C++ Lab environment, the problem can be solved by storing customer, vehicle, and servicing information in appropriate database tables and then using an SQL aggregate query to calculate the total expenditure of each customer. The result can then be displayed through a C++ program connected to the database. A suitable database design may contain tables such as `Customer`, `Vehicle`, and `Service`. The `Customer` table can store customer information such as `CustomerID`, `CustomerName`, phone number, and address. The `Vehicle` table can store `VehicleID`, `CustomerID`, vehicle registration number, model, and vehicle type. The `Service` table can contain service details such as `ServiceID`, `VehicleID`, service date, service description, and service cost. The `CustomerID` connects a customer with one or more vehicles, while `VehicleID` connects each vehicle with its servicing records. For example, the tables may be represented as follows: ```sql CREATE TABLE Customer ( CustomerID INT PRIMARY KEY, CustomerName VARCHAR(100), Phone VARCHAR(15), Address VARCHAR(200) ); CREATE TABLE Vehicle ( VehicleID INT PRIMARY KEY, CustomerID INT, RegistrationNo VARCHAR(20), Model VARCHAR(50), FOREIGN KEY (CustomerID) REFERENCES Customer(CustomerID) ); CREATE TABLE Service ( ServiceID INT PRIMARY KEY, VehicleID INT, ServiceDate DATE, ServiceDescription VARCHAR(200), ServiceCost DECIMAL(10,2), FOREIGN KEY (VehicleID) REFERENCES Vehicle(VehicleID) ); ``` The main requirement is to display the five customers who have spent the highest amount on vehicle servicing. Since a customer may own more than one vehicle and each