Struct CalculatedMeasure 

pub struct CalculatedMeasure { /* private fields */ }

A calculated measure derived from an expression

Calculated measures are derived from other measures or dimensions using SQL-like expressions. They’re computed at query time using DataFusion’s expression engine.

Examples

// profit = revenue - cost
let profit = CalculatedMeasure::new(
    "profit",
    "revenue - cost",
    DataType::Float64,
    AggFunc::Sum
)?;

// margin = (profit / revenue) * 100
let margin = CalculatedMeasure::new(
    "margin",
    "(profit / revenue) * 100",
    DataType::Float64,
    AggFunc::Avg
)?;

Implementations

impl CalculatedMeasure

pub fn new( name: impl Into<String>, expression: impl Into<String>, data_type: DataType, default_agg: AggFunc, ) -> Result<Self>

Create a new calculated measure

Arguments

• name - Name for the calculated measure
• expression - SQL expression (e.g., “revenue - cost”)
• data_type - Expected result data type
• default_agg - Default aggregation function

Returns

A new CalculatedMeasure instance

pub fn name(&self) -> &str

Get the measure name

pub fn expression(&self) -> &str

Get the SQL expression

pub fn data_type(&self) -> &DataType

Get the data type

pub fn default_agg(&self) -> AggFunc

Get the default aggregation function

pub fn is_nullable(&self) -> bool

Check if the measure is nullable

pub fn description(&self) -> Option<&str>

Get the description

pub fn format(&self) -> Option<&str>

Get the format string

pub fn with_nullable(self, nullable: bool) -> Self

Builder-style: set nullable

pub fn with_description(self, description: impl Into<String>) -> Self

Builder-style: set description

pub fn with_format(self, format: impl Into<String>) -> Self

Builder-style: set format

Trait Implementations

impl Clone for CalculatedMeasure

fn clone(&self) -> CalculatedMeasure

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for CalculatedMeasure

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for CalculatedMeasure

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for CalculatedMeasure

fn eq(&self, other: &CalculatedMeasure) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for CalculatedMeasure

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for CalculatedMeasure