16.10 - Typical Query Rewrite Techniques - Teradata Database

Teradata Database SQL Request and Transaction Processing

prodname
Teradata Database
vrm_release
16.10
created_date
June 2017
category
Programming Reference
User Guide
featnum
B035-1142-161K

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 sections discuss various techniques Teradata Database uses to rewrite submitted queries for faster processing.