Interface FlinkMetadata.ColumnNullCount
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- 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.
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Nested Class Summary
Nested Classes Modifier and Type Interface Description static interface
FlinkMetadata.ColumnNullCount.Handler
Handler API.
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Field Summary
Fields Modifier and Type Field Description static org.apache.calcite.rel.metadata.MetadataDef<FlinkMetadata.ColumnNullCount>
DEF
static Method
METHOD
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description Double
getColumnNullCount(int index)
Returns the null count of the given column from a specified relational expression.
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Field Detail
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METHOD
static final Method METHOD
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DEF
static final org.apache.calcite.rel.metadata.MetadataDef<FlinkMetadata.ColumnNullCount> DEF
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Method Detail
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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.
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