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Practice Comparison

Explore how to apply SQL comparison patterns to solve practical problems related to customer orders, product-supplier relationships, and sales data. Learn to write queries that identify customers with multiple orders and no late deliveries, unique product pairs by supplier, and top-selling products. This lesson enhances your ability to analyze data with advanced comparison techniques.

Comparison patterns questions

Let’s practice writing queries to strengthen your grasp of comparison patterns.

Customers with multiple orders who have never received a delivery late

Given the following structure of the Orders table:

Field

Type

OrderID

int

CustomerID

int

OrderDate

date

TotalAmount

decimal(10,2)

ShippedDate

date

DeliveryStatus

enum('Pending','Shipped','Delivered','Cancelled')

EmployeeID

int

CreatedAt

timestamp

ExpectedDeliveryDate

date

ActualDeliveryDate

date

LateDelivery

tinyint(1)

PaymentMethod

enum('Credit Card','PayPal','Cash on Delivery')

ReturnCount

int

FraudRisk

tinyint(1)

Where OrderID is the primary key and CustomerID is the foreign key from the Customers table referring to the customer who placed the order. The table contains information about the orders placed.

Write an SQL query to find all customers who have:

  • Placed ...