Identifies the sample to which a row belongs, distinguishing rows belonging to different samples specified in the SAMPLE clause of a SELECT statement.
where:
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Syntax element … |
Specifies … |
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SAMPLEID |
a select list or ORDER BY clause expression that indicates that sample identifiers are to be used to link result set rows with their originating samples. |
SAMPLEID is a Teradata extension to the ANSI SQL:2011 standard.
The sample ID identifies the sample to which a row belongs in the left-to-right order of the SAMPLE clause specification, from 1 through n (where n is the number of samples requested in the SAMPLE clause).
The rules and restrictions are:
The SAMPLEID value for stratified sampling is simply 1, 2, 3, … n across n specified samples regardless of stratification. That is, for the following SAMPLE clause,
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SAMPLE WHEN state = 'CA' THEN
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0.3,
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0.2
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ELSE
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0.5,
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0.2
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the SAMPLEID correspondence would be: |
1 |
2 |
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3 |
4 |
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