diesel/expression/
select_by.rs

1use crate::backend::{Backend, DieselReserveSpecialization};
2use crate::dsl::SqlTypeOf;
3use crate::expression::{
4    AppearsOnTable, Expression, QueryMetadata, Selectable, SelectableExpression,
5    TypedExpressionType, ValidGrouping,
6};
7use crate::query_builder::*;
8use crate::result::QueryResult;
9use alloc::vec::Vec;
10
11#[derive(#[automatically_derived]
impl<T: ::core::fmt::Debug + Selectable<DB>, DB: ::core::fmt::Debug + Backend>
    ::core::fmt::Debug for SelectBy<T, DB> where
    T::SelectExpression: ::core::fmt::Debug {
    #[inline]
    fn fmt(&self, f: &mut ::core::fmt::Formatter) -> ::core::fmt::Result {
        ::core::fmt::Formatter::debug_struct_field2_finish(f, "SelectBy",
            "selection", &self.selection, "p", &&self.p)
    }
}Debug)]
12pub struct SelectBy<T: Selectable<DB>, DB: Backend> {
13    selection: T::SelectExpression,
14    p: core::marker::PhantomData<(T, DB)>,
15}
16
17impl<T, DB> Clone for SelectBy<T, DB>
18where
19    DB: Backend,
20    T: Selectable<DB>,
21{
22    fn clone(&self) -> Self {
23        Self {
24            selection: T::construct_selection(),
25            p: core::marker::PhantomData,
26        }
27    }
28}
29
30impl<T, DB> Copy for SelectBy<T, DB>
31where
32    T: Selectable<DB>,
33    DB: Backend,
34    T::SelectExpression: Copy,
35{
36}
37
38impl<T, E, DB> QueryId for SelectBy<T, DB>
39where
40    DB: Backend,
41    T: Selectable<DB, SelectExpression = E>,
42    E: QueryId + Expression,
43{
44    type QueryId = E::QueryId;
45
46    const HAS_STATIC_QUERY_ID: bool = E::HAS_STATIC_QUERY_ID;
47}
48
49impl<T, DB> SelectBy<T, DB>
50where
51    T: Selectable<DB>,
52    DB: Backend,
53{
54    pub(crate) fn new() -> Self {
55        Self {
56            selection: T::construct_selection(),
57            p: core::marker::PhantomData,
58        }
59    }
60}
61
62impl<T, E, DB> Expression for SelectBy<T, DB>
63where
64    DB: Backend,
65    T: Selectable<DB, SelectExpression = E>,
66    E: QueryId + Expression,
67{
68    type SqlType = SelectBy<T, DB>;
69}
70
71impl<T, DB> TypedExpressionType for SelectBy<T, DB>
72where
73    T: Selectable<DB>,
74    DB: Backend,
75{
76}
77
78impl<T, GB, E, DB> ValidGrouping<GB> for SelectBy<T, DB>
79where
80    DB: Backend,
81    T: Selectable<DB, SelectExpression = E>,
82    E: Expression + ValidGrouping<GB>,
83{
84    type IsAggregate = E::IsAggregate;
85}
86
87impl<T, DB> QueryMetadata<SelectBy<T, DB>> for DB
88where
89    DB: Backend,
90    T: Selectable<DB>,
91    DB: QueryMetadata<SqlTypeOf<T::SelectExpression>>,
92{
93    fn row_metadata(lookup: &mut Self::MetadataLookup, out: &mut Vec<Option<Self::TypeMetadata>>) {
94        <DB as QueryMetadata<SqlTypeOf<<T as Selectable<DB>>::SelectExpression>>>::row_metadata(
95            lookup, out,
96        )
97    }
98}
99
100impl<T, DB> QueryFragment<DB> for SelectBy<T, DB>
101where
102    T: Selectable<DB>,
103    T::SelectExpression: QueryFragment<DB>,
104    DB: Backend + DieselReserveSpecialization,
105{
106    fn walk_ast<'b>(&'b self, out: AstPass<'_, 'b, DB>) -> QueryResult<()> {
107        self.selection.walk_ast(out)
108    }
109}
110
111impl<T, QS, DB> SelectableExpression<QS> for SelectBy<T, DB>
112where
113    DB: Backend,
114    T: Selectable<DB>,
115    T::SelectExpression: SelectableExpression<QS>,
116    Self: AppearsOnTable<QS>,
117{
118}
119
120impl<T, QS, DB> AppearsOnTable<QS> for SelectBy<T, DB>
121where
122    DB: Backend,
123    T: Selectable<DB>,
124    T::SelectExpression: AppearsOnTable<QS>,
125    Self: Expression,
126{
127}
diesel/expression/select_by.rs

diesel/expression/
select_by.rs
