Hive HPL/SQL is a tool that implements procedural SQL for Hive.
HPL/SQL language is compatible to a large extent with Oracle PL/SQL, ANSI/ISO SQL/PSM (IBM DB2, MySQL, Teradata i.e), PostgreSQL PL/pgSQL (PostgreSQL, Netezza) and Transact-SQL (Microsoft SQL Server and Sybase) that facilitates migration of existing business logic to Hadoop.
See HPL/SQL Reference for documentation.