17.05 - Example: Join Before Expansion - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - SQL Data Manipulation Language

Product
Advanced SQL Engine
Teradata Database
Release Number
17.05
Published
January 2021
Language
English (United States)
Last Update
2021-01-22
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Following are the table definitions for this example:

     CREATE SET TABLE DR.t3, NO FALLBACK , NO BEFORE JOURNAL,
                             NO AFTER JOURNAL, CHECKSUM = DEFAULT (
       a  INTEGER,
       b  INTEGER,
       pd PERIOD(TIMESTAMP(6)))
     PRIMARY INDEX (a);
     CREATE SET TABLE DR.t4, NO FALLBACK, NO BEFORE JOURNAL,
                             NO AFTER JOURNAL, CHECKSUM = DEFAULT (
       x  INTEGER NOT NULL,
       y  INTEGER NOT NULL,
       pd PERIOD(DATE))
     PRIMARY INDEX (x);

This example shows how the database joins the tables specified in an EXPAND ON clause when the specified period expression specifies a column from a table that is not specified in the FROM clause .

     SELECT expd
             FROM t4
             EXPAND ON t3.pd AS expd;

An EXPLAIN shows a JOIN with t3.