Collecting QCD Statistics on Multiple Columns - Analytics Database - Teradata Vantage

SQL Data Manipulation Language

Deployment
VantageCloud
VantageCore
Edition
Enterprise
IntelliFlex
VMware
Product
Analytics Database
Teradata Vantage
Release Number
17.20
Published
June 2022
Language
English (United States)
Last Update
2024-04-05
dita:mapPath
pon1628111750298.ditamap
dita:ditavalPath
qkf1628213546010.ditaval
dita:id
esx1472246586715
lifecycle
latest
Product Category
Teradata Vantage™

If you have defined a column set as a composite index, it makes no difference whether you collect statistics on the composite using the COLUMN keyword or the INDEX keyword. The result is identical.

For example, suppose you have created an index on the column set (x1,y1) of table t1. The following COLLECT STATISTICS requests gather the identical statistics for the named QCD into the identical QCD table columns:

     COLLECT STATISTICS FOR SAMPLE 30 PERCENT ON t1
       INTO myqcd COLUMN (x1,y1);

     COLLECT STATISTICS FOR SAMPLE 30 PERCENT ON t1
       INTO myqcd INDEX (x1,y1);