Never

diesel::expression::is_aggregate

Struct Never 

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pub struct Never;
Expand description

This expression is never aggregate, and can appear with any other expression, regardless of whether it is aggregate.

Examples of this are literals. 1 does not care about aggregation. foo + 1 is always valid, regardless of whether foo appears in the group by clause or not.

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impl MixedAggregates<Never> for No

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type Output = No

What is the resulting IsAggregate type?
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impl MixedAggregates<Never> for Yes

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type Output = Yes

What is the resulting IsAggregate type?
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impl<T> MixedAggregates<T> for Never

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type Output = T

What is the resulting IsAggregate type?

Auto Trait Implementations§

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impl Freeze for Never

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impl RefUnwindSafe for Never

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impl Send for Never

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impl Sync for Never

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impl Unpin for Never

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impl UnwindSafe for Never

Blanket Implementations§

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impl<T> AggregateExpressionMethods for T

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fn aggregate_distinct(self) -> AggregateDistinct<Self>
where Self: DistinctDsl,

DISTINCT modifier for aggregate functions Read more
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fn aggregate_all(self) -> AggregateAll<Self>
where Self: AllDsl,

ALL modifier for aggregate functions Read more
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fn aggregate_filter<P>(self, f: P) -> AggregateFilter<Self, P>
where P: AsExpression<Bool>, Self: FilterDsl<P::Expression>,

Add an aggregate function filter Read more
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fn aggregate_order<O>(self, o: O) -> AggregateOrder<Self, O>
where Self: OrderAggregateDsl<O>,

Add an aggregate function order Read more
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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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

Mutably borrows from an owned value. Read more
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impl<T> Downcast for T
where T: Any,

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fn into_any(self: Box<T>) -> Box<dyn Any>

Converts Box<dyn Trait> (where Trait: Downcast) to Box<dyn Any>, which can then be downcast into Box<dyn ConcreteType> where ConcreteType implements Trait.
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fn into_any_rc(self: Rc<T>) -> Rc<dyn Any>

Converts Rc<Trait> (where Trait: Downcast) to Rc<Any>, which can then be further downcast into Rc<ConcreteType> where ConcreteType implements Trait.
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fn as_any(&self) -> &(dyn Any + 'static)

Converts &Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &Any’s vtable from &Trait’s.
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fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)

Converts &mut Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &mut Any’s vtable from &mut Trait’s.
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impl<T> DowncastSend for T
where T: Any + Send,

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fn into_any_send(self: Box<T>) -> Box<dyn Any + Send>

Converts Box<Trait> (where Trait: DowncastSend) to Box<dyn Any + Send>, which can then be downcast into Box<ConcreteType> where ConcreteType implements Trait.
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impl<T> DowncastSync for T
where T: Any + Send + Sync,

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fn into_any_sync(self: Box<T>) -> Box<dyn Any + Send + Sync>

Converts Box<Trait> (where Trait: DowncastSync) to Box<dyn Any + Send + Sync>, which can then be downcast into Box<ConcreteType> where ConcreteType implements Trait.
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fn into_any_arc(self: Arc<T>) -> Arc<dyn Any + Send + Sync>

Converts Arc<Trait> (where Trait: DowncastSync) to Arc<Any>, which can then be downcast into Arc<ConcreteType> where ConcreteType implements Trait.
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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

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fn into(self) -> U

Calls U::from(self).

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

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impl<T> IntoSql for T

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fn into_sql<T>(self) -> AsExprOf<Self, T>
where Self: AsExpression<T> + Sized, T: SqlType + TypedExpressionType,

Convert self to an expression for Diesel’s query builder. Read more
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fn as_sql<'a, T>(&'a self) -> AsExprOf<&'a Self, T>
where &'a Self: AsExpression<T>, T: SqlType + TypedExpressionType,

Convert &self to an expression for Diesel’s query builder. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<T> WindowExpressionMethods for T

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fn over(self) -> Over<Self>
where Self: OverDsl,

Turn a function call into a window function call Read more
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fn window_filter<P>(self, f: P) -> WindowFilter<Self, P>
where P: AsExpression<Bool>, Self: FilterDsl<P::Expression>,

Add a filter to the current window function Read more
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fn partition_by<E>(self, expr: E) -> PartitionBy<Self, E>
where Self: PartitionByDsl<E>,

Add a partition clause to the current window function Read more
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fn window_order<E>(self, expr: E) -> WindowOrder<Self, E>
where Self: OrderWindowDsl<E>,

Add a order clause to the current window function Read more
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fn frame_by<E>(self, expr: E) -> FrameBy<Self, E>
where Self: FrameDsl<E>,

Add a frame clause to the current window function Read more
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impl<T> ErasedDestructor for T
where T: 'static,