Amazon Athena provides assistance for User Defined Functions (UDF)

Amazon Athena is an interactive query service which makes simple to study data straight in Amazon S3 with the help of standard SQL. You do not need to handle any infrastructure as Amazon Athena is serverless. Athena is simple to utilize. Simply point to your data in Amazon S3, specify the schema, and begin querying using standard SQL to execute ad-hoc queries and you will get results within seconds with few clicks in AWS management console. There is no necessity for complex ETL jobs to make your data for analysis with Amazon Athena. This makes it simple to SQL expertise to faster explore large-scale datasets. Now Amazon Athena offers new feature i.e. user-defined functions (UDFs), a feature which allows users to write custom scalar functions and call them in SQL queries. While Amazon Athena presents built-in functions, UDFs allow users to execute custom processing like compressing and decompressing data, redacting sensitive data, or applying customized decryption. Using Athena Query Federation SDK users can write their UDFs in Java. When a UDF is used in a SQL query submitted to Athena, it is called and performed on AWS Lambda. UDFs can be utilized in both SELECT and FILTER clauses of a SQL query. Users can call several UDFs in the same query. This new Athena UDF feature is accessible in Preview mode in the us-east-1 (N. Virginia) region. You can follow these steps to start your Preview. To know more on User Define Functions (UDF), read documentation. You can get UDF example implementations here. And to know further how to write your functions with Athena Query Federation SDK, go through this link.