User-Defined Function (UDF)

A User-Defined Function (UDF) allows users to extend the built-in capabilities of a query language like SQL by writing custom code to perform specific logic. In RisingWave, UDFs can be written in languages like Python, Java, or Rust and can perform scalar computations (acting on single rows), aggregations, or even generate table outputs. They enable embedding complex business logic or specialized calculations directly into streaming queries.