Working with databases often means dealing with missing or undefined data represented by NULL values. This is where the Coalesce SQL function comes in handy. COALESCE evaluates a list of expressions and returns the first non-NULL value, making it an essential tool for writing clean and reliable queries. For example, you can use it to display default values when data is missing, prevent errors in calculations, or combine multiple columns into a single output. In this beginner-friendly guide, you’ll learn what Coalesce SQL is, how it works, and why it’s widely used by developers and data analysts. With practical examples, you’ll see how it simplifies query results, improves reporting accuracy, and ensures better data handling. Whether you’re new to SQL or looking to refine your database skills, mastering COALESCE will make your queries smarter and your data management much more efficient.