Data exchange with INSERT

To extract data from tables/partitions, we can use the INSERT keyword. Like other relational databases, Hive supports inserting data into a table by selecting data from another table. This is a very common ETL (a term in data warehousing for Extract, Transform, and Load) pattern used to populate an existing or new table from another table or dataset. The HQL INSERT statement has the same syntax as a relational database's INSERT. However, HQL has improved its INSERT statement by supporting data overwrittening, multi-insert, dynamic partition insert, as well as inserting data into files. The following are a few examples of INSERT statements in HQL:

1. The following is a regular INSERT from the SELECT statement:

      -- Check the target table, which is empty.
      > SELECT name, work_place FROM employee;
      +-------------+-------------------+
 ...