Examples of Query Rewrites | SQL Request and Transaction Processing | Vantage - 17.10 - Examples of Query Rewrites - Advanced SQL Engine - Teradata Database

Teradata Vantageā„¢ - SQL Request and Transaction Processing

Product
Advanced SQL Engine
Teradata Database
Release Number
17.10
Release Date
July 2021
Content Type
Programming Reference
User Guide
Publication ID
B035-1142-171K
Language
English (United States)

Because relational systems are based on rigorous mathematical principles, there is a good deal of algebraic simplification and term reduction that can be made for most queries. Similarly, there are often semantically equivalent operations that can be substituted for analytically more difficult operations in order to simplify processing. The vast majority of these semantically equivalent rewrites cannot be specified in the query itself, examples being the substitution of a join index for an explicitly specified join operation and the pushing of projections.

The following examples show how Vantage rewrites submitted queries for faster processing.