Azure SQL Database is a cloud-based relational database service provided by Microsoft Azure. It allows users to store, manage, and analyze data using SQL (Structured Query Language). This service is designed for high availability, scalability, and security, making it suitable for various applications, from small websites to large enterprise systems. With Azure SQL Database, users can easily set up and manage databases without the need for physical hardware. It offers features like automatic backups, built-in intelligence for performance tuning, and support for various programming languages. This makes it a flexible and efficient solution for developers and businesses alike.