Hive has in-built functions to perform operations on columns with a specific datatype. The date functions can help in dealing with date columns, string functions can help in extracting or modifying the string, and maths functions can do calculations on numerical data. Although Hive provides many in-built functions for users, sometimes users may want to have functions that are not on the list of Hive's in-built functions and therefore Hive provides user-defined functions (UDF). Hive UDFs provide the ability to build your own functions that are not present in the Hive function library. Hive UDFs are written in Java and they can be created by implementing specific classes provided by the Hive interface.
Let's create one UDF that removes ...
