Coalesce

Coalesce is a programming concept that returns the first non-null or non-null-like value (e.g., null, undefined, nil) from a list of expressions. It is commonly used to handle missing or default values in a concise way, avoiding verbose null checks. This concept is implemented as a built-in function or operator in many programming languages and databases.

Also known as: COALESCE, coalesce operator, null coalescing, ?? operator, ISNULL/NVL (in some contexts)

Why learn Coalesce?

Developers should use coalesce when they need to provide fallback values for potentially null variables, such as in data processing, user input handling, or database queries. It simplifies code by reducing conditional logic, making it more readable and less error-prone, especially in scenarios like setting default values or aggregating data with missing entries.

Learning Resources

• docs: MDN Web Docs: Nullish coalescing operator (??)
• docs: PostgreSQL Documentation: COALESCE
• tutorial: W3Schools SQL COALESCE Function
• tutorial: C# Null-Coalescing Operator Tutorial
• video: YouTube: Understanding Coalesce in Programming