pub struct AggregateUDF {
    pub name: String,
    pub signature: Signature,
    pub return_type: ReturnTypeFunction,
    pub accumulator: AccumulatorFactoryFunction,
    pub state_type: StateTypeFunction,
}
Expand description

Logical representation of a user-defined aggregate function (UDAF).

An aggregate function combines the values from multiple input rows into a single output “aggregate” (summary) row. It is different from a scalar function because it is stateful across batches. User defined aggregate functions can be used as normal SQL aggregate functions (GROUP BY clause) as well as window functions (OVER clause).

AggregateUDF provides DataFusion the information needed to plan and call aggregate functions, including name, type information, and a factory function to create Accumulator, which peform the actual aggregation.

For more information, please see the examples.

Fields§

§name: String

name

§signature: Signature

Signature (input arguments)

§return_type: ReturnTypeFunction

Return type

§accumulator: AccumulatorFactoryFunction

actual implementation

§state_type: StateTypeFunction

the accumulator’s state’s description as a function of the return type

Implementations§

source§

impl AggregateUDF

source

pub fn new( name: &str, signature: &Signature, return_type: &ReturnTypeFunction, accumulator: &AccumulatorFactoryFunction, state_type: &StateTypeFunction ) -> Self

Create a new AggregateUDF

source

pub fn call(&self, args: Vec<Expr>) -> Expr

creates an Expr that calls the aggregate function.

This utility allows using the UDAF without requiring access to the registry, such as with the DataFrame API.

Trait Implementations§

source§

impl Clone for AggregateUDF

source§

fn clone(&self) -> AggregateUDF

Returns a copy of the value. Read more
1.0.0 · source§

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

Performs copy-assignment from source. Read more
source§

impl Debug for AggregateUDF

source§

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

Formats the value using the given formatter. Read more
source§

impl Hash for AggregateUDF

source§

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher. Read more
1.3.0 · source§

fn hash_slice<H>(data: &[Self], state: &mut H)where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
source§

impl PartialEq<AggregateUDF> for AggregateUDF

source§

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

This method tests for self and other values to be equal, and is used by ==.
1.0.0 · source§

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

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
source§

impl Eq for AggregateUDF

Auto Trait Implementations§

Blanket Implementations§

source§

impl<T> Any for Twhere T: 'static + ?Sized,

source§

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
source§

impl<T> Borrow<T> for Twhere T: ?Sized,

source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
source§

impl<T> BorrowMut<T> for Twhere T: ?Sized,

source§

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
§

impl<Q, K> Equivalent<K> for Qwhere Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

§

fn equivalent(&self, key: &K) -> bool

Checks if this value is equivalent to the given key. Read more
§

impl<Q, K> Equivalent<K> for Qwhere Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

§

fn equivalent(&self, key: &K) -> bool

Compare self to key and return true if they are equal.
source§

impl<T> From<T> for T

source§

fn from(t: T) -> T

Returns the argument unchanged.

source§

impl<T, U> Into<U> for Twhere U: From<T>,

source§

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

source§

impl<T> ToOwned for Twhere T: Clone,

§

type Owned = T

The resulting type after obtaining ownership.
source§

fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
source§

fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
source§

impl<T, U> TryFrom<U> for Twhere U: Into<T>,

§

type Error = Infallible

The type returned in the event of a conversion error.
source§

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
source§

impl<T, U> TryInto<U> for Twhere U: TryFrom<T>,

§

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
source§

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.