org.apache.flink.table.planner.plan.metadata

Interface FlinkMetadata.ColumnNullCount

All Superinterfaces:

org.apache.calcite.rel.metadata.Metadata

Enclosing class:

FlinkMetadata

public static interface FlinkMetadata.ColumnNullCount
extends org.apache.calcite.rel.metadata.Metadata

Metadata about the null count of given column from a specified relational expression.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	FlinkMetadata.ColumnNullCount.Handler Handler API.

Field Summary

Fields

Modifier and Type	Field and Description
static org.apache.calcite.rel.metadata.MetadataDef<FlinkMetadata.ColumnNullCount>	DEF
static Method	METHOD

Method Summary

Modifier and Type	Method and Description
Double	getColumnNullCount(int index) Returns the null count of the given column from a specified relational expression.

Methods inherited from interface org.apache.calcite.rel.metadata.Metadata

rel

Field Detail

METHOD

static final Method METHOD

DEF

static final org.apache.calcite.rel.metadata.MetadataDef<FlinkMetadata.ColumnNullCount> DEF

Method Detail

getColumnNullCount

Double getColumnNullCount(int index)

Returns the null count of the given column from a specified relational expression.

Parameters:

index - the index of the given column in a specified relational expression

Returns:

the null count of the given column if can be estimated, else return null.