Northwind
Customer & Product
Analysis

-- Which 5 countries have the most customers?
SELECT Customers.Country, COUNT(Customers.CustomerID) AS 'Number of Customers'
FROM Customers
GROUP BY Customers.Country
ORDER BY COUNT(Customers.CustomerID) DESC
LIMIT 5;

-- What are the minimum, maximum, and average product prices?
SELECT
  MIN(Products.Price) AS 'Min Price',
  MAX(Products.Price) AS 'Max Price',
  AVG(Products.Price) AS 'Average Price'
FROM Products;

-- Who are the top 10 customers by order frequency?
SELECT
  Orders.CustomerID AS 'Customer_ID',
  COUNT(Orders.OrderID) AS 'Number of Orders'
FROM Orders
GROUP BY Orders.CustomerID
ORDER BY COUNT(Orders.OrderID) DESC
LIMIT 10;

-- Which products are priced above the overall average?
SELECT Products.ProductName, Products.Price
FROM Products
WHERE Products.Price > (SELECT AVG(Products.Price) FROM Products)
ORDER BY Products.Price DESC;

-- Are there customers who have never placed an order?
SELECT
  Customers.CustomerID,
  Customers.CustomerName,
  Customers.Country
FROM Customers
WHERE Customers.CustomerID NOT IN (
  SELECT DISTINCT Orders.CustomerID
  FROM Orders
)
ORDER BY CAST(Customers.CustomerID AS UNSIGNED) ASC;