How do I remove duplicates from Hive table?

To remove duplicate values, you can use insert overwrite table in Hive using the DISTINCT keyword while selecting from the original table. The DISTINCT keyword returns unique records from the table.

How would you delete the data of Hive table without deleting the table?

The goal is to destroy a Hive schema but keep the data underneath. Given a Hive external table, created for example with script 1, it can be dropped with script 2. This deletes the data (removes the folder /user/me/data/ ).

Can we delete data from Hive table?

Apache Hive is not designed for online transaction processing and does not offer real-time queries and row level updates and deletes. To use ACID transaction, one must create a table with ACID transaction properties set. Delete can be performed on the table that supports ACID.

How do I find duplicate records in hive?

select primary_key1, primary_key2, count(*) from mytable group by primary_key1, primary_key2 having count(*) > 1; Above query should list of rows which are duplicated and how many times particular row is duplicated.

What happens if we drop Managed table in Hive?

It is the default table in Hive. When the user creates a table in Hive without specifying it as external, then by default, an internal table gets created in a specific location in HDFS. If we drop the managed table or partition, the table data and the metadata associated with that table will be deleted from the HDFS.

Will retain the table data once the table is dropped?

When a table is dropped, the data in case of managed tables gets cleaned up. However for an external table only the metadata of the table is cleared and the data still persists as it is in its place.

How do I delete data from an external table?

You cannot delete or truncate an external table. However, you can alter and drop the table definition. Dropping an external table drops the table definition, but it does not delete the data file that is associated with the table. To drop an external table, use the DROP statement.

Can we update records in Hive table?

Hive does not support UPDATE option. But the following alternative could be used to achieve the result: Update records in a partitioned Hive table : The main table is assumed to be partitioned by some key.

Is it possible to overwrite Hadoop MapReduce configuration in hive?

14) Is it possible to overwrite Hadoop MapReduce configuration in Hive? Yes, hadoop MapReduce configuration can be overwritten by changing the hive conf settings file.