Hive is an open-source, data warehouse and analytic package that runs on top of Hadoop. Hive scripts use an SQL-like language called Hive QL (query language) that abstracts the MapReduce programming model and supports typical data warehouse interactions. Hive enables you to avoid the complexities of writing MapReduce programs in a lower level computer language, such as Java.
Hive extends the SQL paradigm by including serialization formats and the ability to invoke mapper and reducer scripts. In contrast to SQL, which only supports primitive value types (such as dates, numbers, and strings), values in Hive tables are structured elements, such as JSON objects, any user-defined data type, or any function written in Java.
For a more information on Hive, go to http://hive.apache.org/.