Struct DerivedField 

pub struct DerivedField<Name, Output>(/* private fields */);

A field exposed by a named derived source.

Trait Implementations

impl<Name, Output> Clone for DerivedField<Name, Output>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<'a, V, Name, Output, Projection, Query> ColumnOf<Derived<'a, V, Name, Projection, Query>> for DerivedField<Name, Output>

where V: SQLParam,

impl<Name, Output> Copy for DerivedField<Name, Output>

impl<Name, Output> Default for DerivedField<Name, Output>

fn default() -> Self

Returns the “default value” for a type.

impl<'a, V, Name, Output> Expr<'a, V> for DerivedField<Name, Output>

where V: SQLParam + 'a, Name: Tag, Output: ProjectionOutput + Expr<'a, V>,

type SQLType = <Output as Expr<'a, V>>::SQLType

The SQL data type this expression evaluates to.

type Nullable = <Output as Expr<'a, V>>::Nullable

Whether this expression can be NULL.

type Aggregate = Scalar

Whether this is an aggregate (COUNT, SUM) or scalar expression.

fn to_expr_sql(&self) -> SQL<'a, V>

Render this value as a scalar expression by reference.

fn into_expr_sql(self) -> SQL<'a, V>

where Self: Sized,

Render this value as a scalar expression, consuming it when useful.

fn to_condition_sql(&self) -> Option<SQL<'a, V>>

Render this value as one element of a ConditionList.

fn into_condition_sql(self) -> Option<SQL<'a, V>>

where Self: Sized,

Consuming counterpart of Expr::to_condition_sql.

impl<Name, Output> ExprValueType for DerivedField<Name, Output>

where Name: Tag, Output: ProjectionOutput + ExprValueType,

type ValueType = <Output as ExprValueType>::ValueType

impl<Name, Output> GroupByIdentity for DerivedField<Name, Output>

where Name: Tag, Output: ProjectionOutput,

type Identity = DerivedField<Name, Output>

impl<Name, Output> HasAggStatus for DerivedField<Name, Output>

where Name: Tag, Output: ProjectionOutput,

type Status = AllScalar

impl<'a, V, Name, Output> IntoGroupBy<'a, V> for DerivedField<Name, Output>

where V: SQLParam + 'a, Name: Tag, Output: ProjectionOutput,

type Columns = Cons<DerivedField<Name, Output>, Nil>

Type-level list of grouped columns (e.g., Cons<Col1, Cons<Col2, Nil>>).

impl<Name, Output> IntoSelectTarget for DerivedField<Name, Output>

where Name: Tag, Output: ProjectionOutput + ExprValueType,

type Marker = SelectCols<(DerivedField<Name, Output>,)>

impl<'a, V, Name, Output> ToSQL<'a, V> for DerivedField<Name, Output>

where V: SQLParam, Name: Tag, Output: ProjectionOutput,

fn to_sql(&self) -> SQL<'a, V>

fn into_sql(self) -> SQL<'a, V>

where Self: Sized,

Consume self and return SQL without cloning. Default delegates to to_sql() (which clones). Types that own their SQL (like SQL and SQLExpr) override this to avoid the clone.