Cardinality and Uniqueness Statistics for the Reasonable Unindexed Join Examples - Teradata Vantage

Teradata® VantageCloud Lake
Deployment
VantageCloud
Edition
Lake
Product
Teradata Vantage
Published
January 2023
ft:locale
en-US
ft:lastEdition
2024-12-11
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phg1621910019905

Dimension Table Cardinality Statistics

For LT/ST-J2a (Reasonable Unindexed) join example, the following row information is given for the small tables:

Attribute Cardinality (rows)
                           color                                               3
                           size                                             10
                           options                                             10

Fact Table Uniqueness Statistics

The following statistics information is given for the large table:

Column Name Number of Unique Values
                           color                                               6
                           size                                             30
                           options                                           300

No index is created on the collection of join columns (color, size, and options) of the large table.

Test Query

The following query is used for the LT/ST-J2a (Reasonable Unindexed) join in this example:

     SELECT *
     FROM widget, color, size, options
     WHERE widgets.color=color.code
     AND   widgets.size=size.code
     AND   widgets.options=options.code
     AND   size.description=options.description;