use Northwind
go
 /* SELECT COUNT(*) AS CustomerCount
 FROM Customers;  */

/* SELECT City, COUNT(*) AS CustomerCount
FROM Customers
GROUP BY City; */

/* SELECT City, COUNT(*) AS CustomerCount
FROM Customers
GROUP BY City
HAVING COUNT(*) >= 3; */

/*  */

-- SELECT * FROM Customers WHERE City = 'London';

-- SELECT City, COUNT(*) AS CustomerCount
-- FROM Customers
-- GROUP BY City
-- HAVING COUNT(*) > 4;

/* SELECT Orders.OrderID, Customers.CompanyName
FROM Orders
INNER JOIN Customers
ON Orders.CustomerID = Customers.CustomerID  */


-- SELECT * FROM Categories C, Products P
-- WHERE C.CategoryID = P.CategoryID;

/* select Country, Region, City from Customers
intersect
select Country, Region, City from Suppliers; */

/* SELECT Orders.OrderID, Customers.CompanyName
FROM Orders
INNER JOIN Customers
ON Orders.CustomerID = Customers.CustomerID;*/

/* SELECT Orders.OrderID, Customers.CompanyName, Employees.FirstName, Employees.LastName
FROM Orders
INNER JOIN Customers
ON Orders.CustomerID = Customers.CustomerID
INNER JOIN Employees
ON Orders.EmployeeID = Employees.EmployeeID; */

/* SELECT Orders.OrderID, Customers.CompanyName, Employees.FirstName, Employees.LastName
FROM Orders
INNER JOIN Customers
ON Orders.CustomerID = Customers.CustomerID
INNER JOIN Employees
ON Orders.EmployeeID = Employees.EmployeeID
WHERE Employees.FirstName = 'Nancy' AND Employees.LastName = 'Davolio'; */

/* SELECT Employees.FirstName, Employees.LastName, COUNT(Orders.OrderID) AS OrderCount
FROM Orders
INNER JOIN Employees
ON Orders.EmployeeID = Employees.EmployeeID
GROUP BY Employees.FirstName, Employees.LastName; */

select ProductID, ProductName, UnitPrice
from Products
where UnitPrice =
(select min (UnitPrice)
from Products);