16.10 - Nested Join Examples - 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

Circumstances for the Nested Join Examples

This section provides the EXPLAIN outputs for the same two-table join under the following circumstances:

  • No nested join
  • A nested join where the USI for one table is joined on a column from the other table.

Table Definitions

For these examples, assume the following table definitions:

Table Name Column 1 Name Column 2 Name Primary Index Name Unique Secondary Index Name Number of Rows
table_1 NUPI        y_1 NUPI none defined                   2
table_2 NUPI        USI_2 NUPI          USI_2     1,000,000

Test Query

The following request is tested against this database, both using and without using nested join:

     SELECT *
     FROM table_1,table_2
     WHERE y_1 = USI_2;