Struct rust_query::group::GroupQuery

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

This is the query type used in sub-queries. It can only produce one result (for each outer result). This type dereferences to Query.

Implementations

impl<'outer, 'inner> GroupQuery<'outer, 'inner>

pub fn filter_on<T: MyIdenT>( &mut self, val: impl Value<'inner, Typ = T>, on: impl Value<'outer, Typ = T> )

Filter the rows of this sub-query based on a value from the outer query.

pub fn avg<V: Value<'inner, Typ = i64>>( &'inner self, val: V ) -> Db<'outer, Option<i64>>

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

pub fn max<V: Value<'inner, Typ = i64>>( &'inner self, val: V ) -> Db<'outer, Option<i64>>

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

pub fn sum_float<V: Value<'inner, Typ = f64>>( &'inner self, val: V ) -> UnwrapOr<Db<'outer, Option<f64>>, f64>

Return the sum of a column.

pub fn count_distinct<V: Value<'inner>>( &'inner self, val: V ) -> UnwrapOr<Db<'outer, Option<i64>>, i64>

Return the number of distinct values in a column.

pub fn exists(&'inner self) -> IsNotNull<Db<'outer, i64>>

Return whether there are any rows.

Methods from Deref<Target = Query<'inner>>

pub fn table<T: HasId>(&mut self, t: T) -> Db<'inner, T>

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

pub fn flat_table<T: Table>(&mut self, t: T) -> T::Dummy<'inner>

Join a table that has no integer primary key. Refer to Query::table for more information about joining tables.

pub fn query<F, R>(&self, f: F) -> R

where F: for<'a> FnOnce(&'a mut GroupQuery<'inner, 'a>) -> R,

Perform a sub-query that returns a single result for each of the current rows.

pub fn filter(&mut self, prop: impl Value<'inner>)

Filter rows based on a column.

pub fn filter_some<T: MyIdenT>( &mut self, val: &Db<'inner, Option<T>> ) -> Db<'inner, T>

Filter out rows where this column is None.

Trait Implementations

impl<'outer, 'inner> Deref for GroupQuery<'outer, 'inner>

type Target = Query<'inner>

The resulting type after dereferencing.

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

Dereferences the value.

impl<'outer, 'inner> DerefMut for GroupQuery<'outer, 'inner>

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

Mutably dereferences the value.