Struct datafusion::functions_aggregate::first_last::FirstValue
source · pub struct FirstValue { /* private fields */ }
Implementations§
source§impl FirstValue
impl FirstValue
pub fn new() -> FirstValue
Trait Implementations§
source§impl AggregateUDFImpl for FirstValue
impl AggregateUDFImpl for FirstValue
source§fn signature(&self) -> &Signature
fn signature(&self) -> &Signature
Returns the function’s
Signature
for information about what input
types are accepted and the function’s Volatility.source§fn return_type(
&self,
arg_types: &[DataType]
) -> Result<DataType, DataFusionError>
fn return_type( &self, arg_types: &[DataType] ) -> Result<DataType, DataFusionError>
What
DataType
will be returned by this function, given the types of
the argumentssource§fn accumulator(
&self,
acc_args: AccumulatorArgs<'_>
) -> Result<Box<dyn Accumulator>, DataFusionError>
fn accumulator( &self, acc_args: AccumulatorArgs<'_> ) -> Result<Box<dyn Accumulator>, DataFusionError>
Return a new
Accumulator
that aggregates values for a specific
group during query execution. Read moresource§fn state_fields(
&self,
name: &str,
value_type: DataType,
ordering_fields: Vec<Field>
) -> Result<Vec<Field>, DataFusionError>
fn state_fields( &self, name: &str, value_type: DataType, ordering_fields: Vec<Field> ) -> Result<Vec<Field>, DataFusionError>
Return the fields used to store the intermediate state of this accumulator. Read more
source§fn aliases(&self) -> &[String]
fn aliases(&self) -> &[String]
Returns any aliases (alternate names) for this function. Read more
source§fn groups_accumulator_supported(&self) -> bool
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. Read moresource§fn create_groups_accumulator(
&self
) -> Result<Box<dyn GroupsAccumulator>, DataFusionError>
fn create_groups_accumulator( &self ) -> Result<Box<dyn GroupsAccumulator>, DataFusionError>
Return a specialized
GroupsAccumulator
that manages state
for all groups. Read moresource§impl Debug for FirstValue
impl Debug for FirstValue
source§impl Default for FirstValue
impl Default for FirstValue
source§fn default() -> FirstValue
fn default() -> FirstValue
Returns the “default value” for a type. Read more
Auto Trait Implementations§
impl Freeze for FirstValue
impl RefUnwindSafe for FirstValue
impl Send for FirstValue
impl Sync for FirstValue
impl Unpin for FirstValue
impl UnwindSafe for FirstValue
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
source§impl<T> IntoEither for T
impl<T> IntoEither for T
source§fn into_either(self, into_left: bool) -> Either<Self, Self>
fn into_either(self, into_left: bool) -> Either<Self, Self>
Converts
self
into a Left
variant of Either<Self, Self>
if into_left
is true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read moresource§fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
Converts
self
into a Left
variant of Either<Self, Self>
if into_left(&self)
returns true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read more