This class makes it very easy, almost trivial, to convert SQL query results into XML, but a major disadvantage of OracleXMLQuery is that it is a proprietary solution.

SQL/XML is another standard that uses declarative, portable queries to return XML by querying relational data. It's an extension of SQL that is part of ANSI/ISO SQL 2003. SQL/XML enables SQL queries ...

Spark SQL: Apache’s Spark project is for real-time, in-memory, parallelized processing of Hadoop data. Spark SQL builds on top of it to allow SQL queries to be written against data.