Struct Aggregate 

pub struct Aggregate<'outer, 'inner, S> { /* private fields */ }

This is the argument type used for aggregate.

Implementations

impl<'outer, 'inner, S: 'static> Aggregate<'outer, 'inner, S>

pub fn avg( &self, val: impl IntoExpr<'inner, S, Typ = f64>, ) -> Expr<'outer, S, Option<f64>>

Return the average value in a column, this is None if there are zero rows.

pub fn max<T>( &self, val: impl IntoExpr<'inner, S, Typ = T>, ) -> Expr<'outer, S, Option<T>>

where T: NumTyp,

Return the maximum value in a column, this is None if there are zero rows.

pub fn min<T>( &self, val: impl IntoExpr<'inner, S, Typ = T>, ) -> Expr<'outer, S, Option<T>>

where T: NumTyp,

Return the minimum value in a column, this is None if there are zero rows.

pub fn sum<T>( &self, val: impl IntoExpr<'inner, S, Typ = T>, ) -> Expr<'outer, S, T>

where T: NumTyp,

Return the sum of a column.

pub fn count_distinct<T: EqTyp + 'static>( &self, val: impl IntoExpr<'inner, S, Typ = T>, ) -> Expr<'outer, S, i64>

Return the number of distinct values in a column.

pub fn exists(&self) -> Expr<'outer, S, bool>

Return whether there are any rows.

Methods from Deref<Target = Rows<'inner, S>>

pub fn join<T: Table<Schema = S>>( &mut self, j: impl Joinable<'inner, Typ = T>, ) -> Expr<'inner, S, T>

Join a table, this is like a super simple Iterator::flat_map but for queries.

After this operation Rows has rows for the combinations of each original row with each row of the table. (Also called the “Carthesian product”)

The expression that is returned refers to the joined table.

pub fn filter(&mut self, prop: impl IntoExpr<'inner, S, Typ = bool>)

Filter rows based on an expression.

pub fn filter_some<Typ: MyTyp>( &mut self, val: impl IntoExpr<'inner, S, Typ = Option<Typ>>, ) -> Expr<'inner, S, Typ>

Filter out rows where this expression is None.

Returns a new expression with the unwrapped type.

Trait Implementations

impl<'inner, S> Deref for Aggregate<'_, 'inner, S>

type Target = Rows<'inner, S>

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl<S> DerefMut for Aggregate<'_, '_, S>

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.