Struct datafusion_expr::expr_fn::SimpleAggregateUDF

pub struct SimpleAggregateUDF { /* private fields */ }

Implements AggregateUDFImpl for functions that have a single signature and return type.

Implementations

impl SimpleAggregateUDF

pub fn new( name: impl Into<String>, input_type: Vec<DataType>, return_type: DataType, volatility: Volatility, accumulator: AccumulatorFactoryFunction, state_type: Vec<DataType> ) -> Self

Create a new AggregateUDFImpl from a name, input types, return type, state type and implementation. Implementing AggregateUDFImpl allows more flexibility

pub fn new_with_signature( name: impl Into<String>, signature: Signature, return_type: DataType, accumulator: AccumulatorFactoryFunction, state_type: Vec<DataType> ) -> Self

Trait Implementations

impl AggregateUDFImpl for SimpleAggregateUDF

fn as_any(&self) -> &dyn Any

Returns this object as an Any trait object

fn name(&self) -> &str

Returns this function’s name

fn signature(&self) -> &Signature

Returns the function’s Signature for information about what input types are accepted and the function’s Volatility.

fn return_type(&self, _arg_types: &[DataType]) -> Result<DataType>

What DataType will be returned by this function, given the types of the arguments

fn accumulator(&self, arg: &DataType) -> Result<Box<dyn Accumulator>>

Return a new Accumulator that aggregates values for a specific group during query execution.

fn state_type(&self, _return_type: &DataType) -> Result<Vec<DataType>>

Return the type used to serialize the Accumulator’s intermediate state. See Accumulator::state() for more details

fn groups_accumulator_supported(&self) -> bool

If the aggregate expression has a specialized GroupsAccumulator implementation. If this returns true, [Self::create_groups_accumulator] will be called.

fn create_groups_accumulator(&self) -> Result<Box<dyn GroupsAccumulator>>

Return a specialized GroupsAccumulator that manages state for all groups.

fn aliases(&self) -> &[String]

Returns any aliases (alternate names) for this function.

impl Debug for SimpleAggregateUDF

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

Formats the value using the given formatter.