16.20 - DROP column_name - Teradata Database - Teradata Vantage NewSQL Engine

Teradata Vantage™ SQL Data Definition Language Syntax and Examples

Product
Teradata Database
Teradata Vantage NewSQL Engine
Release Number
16.20
Published
March 2019
Language
English (United States)
Last Update
2019-05-24
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Removes the named column from the table. 
You cannot drop the QITS column from a queue table. For a column-partitioned table, Teradata Database drops the specified column from its column partition. 
If the specified column is the only column in the column partition, and the partition is not the only column partition, Teradata Database drops the partition. You cannot drop a column partition with a single column when it is the only column partition defined for the table or join index. You cannot drop a column in use as the begin column or end column of a derived period column.

For information about dropping temporal columns, see Teradata Vantage™ Temporal Table Support , B035-1182 .

IDENTITY
Removes the identity column attribute for the named column from the table. 
The specification of IDENTITY is optional.
You can drop an identity column from an existing table. 
When you use Teradata Unity, you cannot do a bulk data load insert of rows into a table that has an identity column. However, you can specify this option to drop only the identity column attribute while retaining the column and data. This is useful when the identity column for a table is also its unique primary index. Teradata Unity provides its own mechanism for generating identity column-like values for tables that require the identity column functionality. For additional information, see the Teradata Unity documentation.