Package org.apache.calcite.sql

Class SqlSampleSpec

java.lang.Object

org.apache.calcite.sql.SqlSampleSpec

Direct Known Subclasses:

SqlSampleSpec.SqlSubstitutionSampleSpec, SqlSampleSpec.SqlTableSampleSpec

public abstract class SqlSampleSpec
extends 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

Modifier and Type	Method	Description
static SqlSampleSpec	createNamed(String name)	Creates a sample which substitutes one relation for another.
static SqlSampleSpec	createTableSample(boolean isBernoulli, float sampleRate)	Deprecated.
static SqlSampleSpec	createTableSample(boolean isBernoulli, float sampleRate, int repeatableSeed)	Deprecated.
static SqlSampleSpec	createTableSample(boolean isBernoulli, BigDecimal sampleRate)	Creates a table sample without repeatability.
static SqlSampleSpec	createTableSample(boolean isBernoulli, BigDecimal sampleRate, 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 Details

SqlSampleSpec

protected SqlSampleSpec()

Method Details

createNamed

public static SqlSampleSpec createNamed(String name)

Creates a sample which substitutes one relation for another.

createTableSample

public static SqlSampleSpec createTableSample(boolean isBernoulli,
 BigDecimal sampleRate)

Creates a table sample without repeatability.

Parameters:

isBernoulli - true if Bernoulli style sampling is to be used; false for implementation specific sampling

sampleRate - likelihood of a row appearing in the sample

createTableSample

@Deprecated
public static SqlSampleSpec createTableSample(boolean isBernoulli,
 float sampleRate)

Deprecated.

createTableSample

public static SqlSampleSpec createTableSample(boolean isBernoulli,
 BigDecimal sampleRate,
 int repeatableSeed)

Creates a table sample with repeatability.

Parameters:

isBernoulli - true if Bernoulli style sampling is to be used; false for implementation specific sampling

sampleRate - likelihood of a row appearing in the sample

repeatableSeed - seed value used to reproduce the same sample

createTableSample

@Deprecated
public static SqlSampleSpec createTableSample(boolean isBernoulli,
 float sampleRate,
 int repeatableSeed)

Deprecated.