MaxCompute provides SQL computing capabilities. In MaxCompute SQL, you can use the system’s built-in functions to perform common computing and counting tasks. If the built-in functions do not meet your requirements, you can use the Java programming interface provided by MaxCompute to develop user-defined functions (UDFs).
UDFs can be divided into scalar valued functions, user-defined aggregate functions (UDAFs), and user-defined tables functions (UDTFs).
For more information, see Function introduction.