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What is a UDF?

🟢 Easy Conceptual Fresher level
1Times asked
Jul 2026Last seen
Jul 2026First seen

💡 Model Answer

UDF stands for User-Defined Function. It is a function created by a user to extend the capabilities of a database or programming environment. In SQL, a UDF can be scalar (returning a single value) or table-valued (returning a set of rows). It allows encapsulation of reusable logic, such as custom calculations or data transformations. In data processing frameworks like Spark, a UDF lets you apply custom logic to DataFrame columns. Example: In PostgreSQL, you might create a UDF to calculate a person's age from a birthdate column. UDFs improve code readability and maintainability by abstracting complex operations.

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