diesel/sql_types/
fold.rs

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1use crate::sql_types::{self, is_nullable, SingleValue, SqlType};
2
3/// Represents SQL types which can be used with `SUM` and `AVG`
4pub trait Foldable: SingleValue {
5    /// The SQL type of `sum(this_type)`
6    type Sum: SqlType + SingleValue;
7    /// The SQL type of `avg(this_type)`
8    type Avg: SqlType + SingleValue;
9}
10
11impl<T> Foldable for sql_types::Nullable<T>
12where
13    T: Foldable + SqlType<IsNull = is_nullable::NotNull>,
14{
15    type Sum = T::Sum;
16    type Avg = T::Avg;
17}
18
19macro_rules! foldable_impls {
20    ($($Source:ty => ($SumType:ty, $AvgType:ty)),+,) => {
21        $(
22            impl Foldable for $Source {
23                type Sum = sql_types::Nullable<$SumType>;
24                type Avg = sql_types::Nullable<$AvgType>;
25            }
26        )+
27    }
28}
29
30foldable_impls! {
31    sql_types::SmallInt => (sql_types::BigInt, sql_types::Numeric),
32    sql_types::Integer => (sql_types::BigInt, sql_types::Numeric),
33    sql_types::BigInt => (sql_types::Numeric, sql_types::Numeric),
34
35    sql_types::Float => (sql_types::Float, sql_types::Double),
36    sql_types::Double => (sql_types::Double, sql_types::Double),
37    sql_types::Numeric => (sql_types::Numeric, sql_types::Numeric),
38
39    sql_types::Interval => (sql_types::Interval, sql_types::Interval),
40}
41
42#[cfg(feature = "mysql_backend")]
43foldable_impls! {
44    sql_types::Unsigned<sql_types::SmallInt> => (sql_types::Unsigned<sql_types::BigInt>, sql_types::Numeric),
45    sql_types::Unsigned<sql_types::Integer> => (sql_types::Unsigned<sql_types::BigInt>, sql_types::Numeric),
46    sql_types::Unsigned<sql_types::BigInt> => (sql_types::Numeric, sql_types::Numeric),
47}
diesel/sql_types/fold.rs

diesel/sql_types/
fold.rs
