How do you drop a Subpartition?

The ALTER TABLE… DROP SUBPARTITION command deletes a subpartition, and the data stored in that subpartition. To use the DROP SUBPARTITION clause, you must be the owner of the partitioning root, a member of a group that owns the table, or have superuser or administrative privileges.

How do I delete a partition in an external Hive table?

This can be achieved as below.

1. Alter external table as internal table — by changing the TBL properties as external =false.
2. Drop the partitions — when you drop the partitions, data pertained to the partitions will also be dropped as now this table is managed table.
3. Alter back the table as external=True.

How do I drop a partition index?

You cannot explicitly drop a partition of a local index. Instead, local index partitions are dropped only when you drop a partition from the underlying table. If a global index partition is empty, then you can explicitly drop it by issuing the ALTER INDEX DROP PARTITION statement.

What is sub partition in hive?

Hive organizes tables into partitions. Tables or partitions are sub-divided into buckets, to provide extra structure to the data that may be used for more efficient querying. Bucketing works based on the value of hash function of some column of a table.

How do I drop all partitions in Oracle?

Use the ALTER TABLE … TRUNCATE PARTITION statement to remove all rows from a table partition. The ALTER TABLE … TRUNCATE PARTITIONS statement does this for multiple partitions.

Will drop partition delete data?

DROP PARTITION command deletes a partition and any data stored on that partition. DROP PARTITION command can drop partitions of a LIST or RANGE partitioned table; please note that this command does not work on a HASH partitioned table.

How do I drop a column in a partitioned table in hive?

7 Answers. You cannot drop column directly from a table using command ALTER TABLE table_name drop col_name; The only way to drop column is using replace command.

How do I remove a partition from a table?

Use one of the following statements to drop a table partition or subpartition:

1. ALTER TABLE DROP PARTITION to drop a table partition.
2. ALTER TABLE DROP SUBPARTITION to drop a subpartition of a composite *-[range | list] partitioned table.

Does dropping partition delete data?

Data itself are stored in files in the partition location(folder). If you drop partition of external table, the location remain untouched, but unmounted as partition (metadata about this partition is deleted).

How do I change the partition column in Hive?

Steps as below.

1. Create Temp table with same columns.
2. Overwrite table with required row data.
3. Drop Hive partitions and HDFS directory.
4. Insert records for respective partitions and rows.
5. verify the counts.

How do I select a partition column in Hive?

CREATE TABLE test_table ( col1 INT, col2 STRING ) PARTITIONED BY (date_col date) stored as textfile; When you use select * from test_table, you will notice, you will get a partition column also in your result. For examples, consider below select clause.

How do I create a drop down partition in Oracle?

ALTER TABLE DROP PARTITION allows you to drop a partition and its data. If you would like to drop the partition but keep its data in the table, the Oracle partition must be merged into one of the adjacent partitions. Note: Far and away, the “drop partition” syntax is the fastest way to remove large volumes of data.