text: /*
  Suppose that a website contains two tables, the Customers table and the Orders table. Write a SQL query to find all customers who never order anything.
  
  Table: Customers.
  +----+-------+
  | Id | Name  |
  +----+-------+
  | 1  | Joe   |
  | 2  | Henry |
  | 3  | Sam   |
  | 4  | Max   |
  +----+-------+
  
  Table: Orders.
  +----+------------+
  | Id | CustomerId |
  +----+------------+
  | 1  | 3          |
  | 2  | 1          |
  +----+------------+
  
  Using the above tables as example, return the following:
  +-----------+
  | Customers |
  +-----------+
  | Henry     |
  | Max       |
  +-----------+
   */
  
  Create table If Not Exists Customers (Id int, Name varchar(255));
  Create table If Not Exists Orders (Id int, CustomerId int);
  Truncate table Customers;
  insert into Customers (Id, Name) values ('1', 'Joe');
  insert into Customers (Id, Name) values ('2', 'Henry');
  insert into Customers (Id, Name) values ('3', 'Sam');
  insert into Customers (Id, Name) values ('4', 'Max');
  Truncate table Orders;
  insert into Orders (Id, CustomerId) values ('1', '3');
  insert into Orders (Id, CustomerId) values ('2', '1');
  
  
  -- Solution
  SELECT
      Customers.Name as 'Customers'
  FROM
      Customers
  WHERE
          Customers.Id NOT IN (
          SELECT
              CustomerId
          from
              Orders
      );
  
  