Sampling Example | Teradata Vantage - Sampling Example: Unconditional, Approximate Sample Size - Teradata Vantage

This example uses the ApproxSampleSize syntax element and a summary (DIMENSION) table as inputs.

Input

• data: score_category, as in Sampling Example: Unconditional, Single Sample Rate
• summary: created from score_category by this query:

  SELECT stratum, COUNT(*) AS stratum_count FROM score_category GROUP BY stratum;

SQL Call

SELECT * FROM Sampling (
  ON (
    SELECT stratum, COUNT(*) AS stratum_count FROM score_category GROUP BY stratum
  ) AS SummaryTable DIMENSION
  ON score_category PARTITION BY ANY
  USING
  ApproxSampleSize (10)
  Seed (2)
) AS dt ORDER BY id;

Output

 id score stratum   
 -- ----- --------- 
  9  65.0 fair     
 23  14.0 fair     
 59  89.0 very good
 61   6.0 fair     
 71  59.0 fair     
 72  79.0 fair     
 75  66.0 fair     
 77  51.0 fair     
 86   6.0 fair     
 89  31.0 fair     
 95  84.0 very good

Download a zip file of all examples and a SQL script file that creates their input tables.