SqlSampleSpec (Apache Calcite API)

java.lang.Object
- org.apache.calcite.sql.SqlSampleSpec

Direct Known Subclasses:

SqlSampleSpec.SqlSubstitutionSampleSpec, SqlSampleSpec.SqlTableSampleSpec
```
public abstract class SqlSampleSpec
extends java.lang.Object
```
Specification of a SQL sample.
For example, the query
```
SELECT *
 FROM emp TABLESAMPLE SUBSTITUTE('medium')
```
declares a sample which is created using createNamed(java.lang.String).

A sample is not a SqlNode. To include it in a parse tree, wrap it as a literal, viz: SqlLiteral.createSample(SqlSampleSpec, org.apache.calcite.sql.parser.SqlParserPos).

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`static class`	`SqlSampleSpec.SqlSubstitutionSampleSpec`	Sample specification that orders substitution.
`static class`	`SqlSampleSpec.SqlTableSampleSpec`	Sample specification.

Constructor Summary

Constructors
Modifier Constructor Description

protected SqlSampleSpec()

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method	Description
`static SqlSampleSpec`	`createNamed(java.lang.String name)`	Creates a sample which substitutes one relation for another.
`static SqlSampleSpec`	`createTableSample(boolean isBernoulli, float samplePercentage)`	Creates a table sample without repeatability.
`static SqlSampleSpec`	`createTableSample(boolean isBernoulli, float samplePercentage, int repeatableSeed)`	Creates a table sample with repeatability.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - SqlSampleSpec
```
protected SqlSampleSpec()
```
- Method Detail
  - createNamed
```
public static SqlSampleSpec createNamed(java.lang.String name)
```
    Creates a sample which substitutes one relation for another.
  - createTableSample
```
public static SqlSampleSpec createTableSample(boolean isBernoulli,
                                              float samplePercentage)
```
    Creates a table sample without repeatability.
    
    Parameters:
    
    isBernoulli - true if Bernoulli style sampling is to be used; false for implementation specific sampling
    
    samplePercentage - likelihood of a row appearing in the sample
  - createTableSample
```
public static SqlSampleSpec createTableSample(boolean isBernoulli,
                                              float samplePercentage,
                                              int repeatableSeed)
```
    Creates a table sample with repeatability.
    
    Parameters:
    
    isBernoulli - true if Bernoulli style sampling is to be used; false for implementation specific sampling
    
    samplePercentage - likelihood of a row appearing in the sample
    
    repeatableSeed - seed value used to reproduce the same sample