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.
    • 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.