17.10 - Specifying the Primary Index for a Hash Index - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - SQL Data Definition Language Detailed Topics

Product
Advanced SQL Engine
Teradata Database
Release Number
17.10
Published
July 2021
Language
English (United States)
Last Update
2021-07-27
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A hash index must have a primary index. Unlike other base tables, you do not use the keywords PRIMARY INDEX to specify the primary index for a hash index.

The following table explains how the primary index for a hash index is defined:

Hash Index Primary Index for the Hash Index Uses this Column Set
Does not define a BY clause Primary index of the base table to which the hash index refers.
Specifies a BY clause and an ORDER BY clause Column set specified in the column_name_2 set in the BY clause.

These columns must also be defined in the column_name_1 set.

Rows in a hash index defined with this type of primary index are ordered either by row hash or by numeric value, depending on what you specify in the ORDER BY clause.