use crate::dsl;
#[cfg(feature = "postgres_backend")]
use crate::expression::SelectableExpression;
use crate::expression::TypedExpressionType;
use crate::expression::ValidGrouping;
use crate::query_builder::FromClause;
use crate::query_builder::{AsQuery, SelectStatement};
use crate::query_source::Table;
use crate::Expression;
pub trait DistinctDsl {
type Output;
fn distinct(self) -> dsl::Distinct<Self>;
}
impl<T> DistinctDsl for T
where
T: Table + AsQuery<Query = SelectStatement<FromClause<T>>>,
T::DefaultSelection: Expression<SqlType = T::SqlType> + ValidGrouping<()>,
T::SqlType: TypedExpressionType,
{
type Output = dsl::Distinct<SelectStatement<FromClause<T>>>;
fn distinct(self) -> dsl::Distinct<SelectStatement<FromClause<T>>> {
self.as_query().distinct()
}
}
#[cfg(feature = "postgres_backend")]
pub trait DistinctOnDsl<Selection> {
type Output;
fn distinct_on(self, selection: Selection) -> dsl::DistinctOn<Self, Selection>;
}
#[cfg(feature = "postgres_backend")]
impl<T, Selection> DistinctOnDsl<Selection> for T
where
Selection: SelectableExpression<T>,
Selection::SqlType: crate::sql_types::SingleValue,
T: Table + AsQuery<Query = SelectStatement<FromClause<T>>>,
SelectStatement<FromClause<T>>: DistinctOnDsl<Selection>,
T::DefaultSelection: Expression<SqlType = T::SqlType> + ValidGrouping<()>,
T::SqlType: TypedExpressionType,
{
type Output = dsl::DistinctOn<SelectStatement<FromClause<T>>, Selection>;
fn distinct_on(self, selection: Selection) -> dsl::DistinctOn<Self, Selection> {
self.as_query().distinct_on(selection)
}
}