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ALTER TABLE ADD COLUMNS
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Last updated: 2024-08-07 17:14:57
ALTER TABLE ADD COLUMNS
Last updated: 2024-08-07 17:14:57
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Description

Supported engines: Presto and SparkSQL
Applicable table: Native Iceberg tables and external tables
Purpose: Change data table attributes.

Standard Statement

ALTER TABLE table_name 
 [PARTITION 
   (partition_col1_name = partition_col1_value
   [,partition_col2_name = partition_col2_value][,...])]
  ADD COLUMNS (col_name data_type) [RESTRICT | CASCADE]

Parameter

table_name: Name of the target table
partition_col1_name: Partitioning column name
partition_col1_value: Partitioning column value
col_name: Name of the column to be added.
data_type: Type of the column to be added.

Example

ALTER TABLE events ADD COLUMNS (eventowner string);

ALTER TABLE events ADD COLUMNS (eventowner string) CASCADE;

//The ALTER TABLE PARTITION ADD COLUMNS statement supports only native DLC tables.
ALTER TABLE events PARTITION (year='2021') ADD COLUMNS (event string);

Caution
If you use the ROW FORMAT SERDE 'org.apache.hive.hcatalog.data.JsonSerDe' format during table creation, you cannot add columns after the table is created. If you use JsonSerDe to create a table, confirm the table structure if possible. If you must add columns, you can delete the existing table and create a new one.

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