diesel/expression/functions/
date_and_time.rs

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1use crate::backend::Backend;
2use crate::expression::coerce::Coerce;
3use crate::expression::functions::define_sql_function;
4use crate::expression::{AsExpression, Expression, ValidGrouping};
5use crate::query_builder::*;
6use crate::result::QueryResult;
7use crate::sql_types::*;
8
9/// Represents the SQL `CURRENT_TIMESTAMP` constant. This is equivalent to the
10/// `NOW()` function on backends that support it.
11#[allow(non_camel_case_types)]
12#[derive(Debug, Copy, Clone, QueryId, ValidGrouping)]
13pub struct now;
14
15impl Expression for now {
16    type SqlType = Timestamp;
17}
18
19impl<DB: Backend> QueryFragment<DB> for now {
20    fn walk_ast<'b>(&'b self, mut out: AstPass<'_, 'b, DB>) -> QueryResult<()> {
21        out.push_sql("CURRENT_TIMESTAMP");
22        Ok(())
23    }
24}
25
26impl_selectable_expression!(now);
27
28operator_allowed!(now, Add, add);
29operator_allowed!(now, Sub, sub);
30define_sql_function! {
31    /// Represents the SQL `DATE` function. The argument should be a Timestamp
32    /// expression, and the return value will be an expression of type Date.
33    ///
34    /// # Examples
35    ///
36    /// ```
37    /// # include!("../../doctest_setup.rs");
38    /// # use diesel::dsl::{now, date};
39    /// # use diesel::deserialize::Queryable;
40    /// #
41    /// # fn test<R: Queryable<diesel::sql_types::Date, DB> + 'static>() -> QueryResult<R> {
42    /// #     let connection = &mut establish_connection();
43    /// let today = diesel::select(date(now)).first(connection)?;
44    /// #     Ok(today)
45    /// # }
46    /// # fn main() {
47    /// #
48    /// # }
49    /// ```
50    fn date(expr: Timestamp) -> Date;
51}
52
53impl AsExpression<Nullable<Timestamp>> for now {
54    type Expression = Coerce<now, Nullable<Timestamp>>;
55
56    fn as_expression(self) -> Self::Expression {
57        Coerce::new(self)
58    }
59}
60
61#[cfg(feature = "postgres_backend")]
62impl AsExpression<Timestamptz> for now {
63    type Expression = Coerce<now, Timestamptz>;
64
65    fn as_expression(self) -> Self::Expression {
66        Coerce::new(self)
67    }
68}
69
70#[cfg(feature = "postgres_backend")]
71impl AsExpression<Nullable<Timestamptz>> for now {
72    type Expression = Coerce<now, Nullable<Timestamptz>>;
73
74    fn as_expression(self) -> Self::Expression {
75        Coerce::new(self)
76    }
77}
78
79#[cfg(feature = "sqlite")]
80impl AsExpression<TimestamptzSqlite> for now {
81    type Expression = Coerce<now, TimestamptzSqlite>;
82
83    fn as_expression(self) -> Self::Expression {
84        Coerce::new(self)
85    }
86}
87
88#[cfg(feature = "sqlite")]
89impl AsExpression<Nullable<TimestamptzSqlite>> for now {
90    type Expression = Coerce<now, Nullable<TimestamptzSqlite>>;
91
92    fn as_expression(self) -> Self::Expression {
93        Coerce::new(self)
94    }
95}
96
97/// Represents the SQL `CURRENT_DATE` constant.
98#[allow(non_camel_case_types)]
99#[derive(Debug, Copy, Clone, QueryId, ValidGrouping)]
100pub struct today;
101
102impl Expression for today {
103    type SqlType = Date;
104}
105
106impl<DB: Backend> QueryFragment<DB> for today {
107    fn walk_ast<'b>(&'b self, mut out: AstPass<'_, 'b, DB>) -> QueryResult<()> {
108        out.push_sql("CURRENT_DATE");
109        Ok(())
110    }
111}
112
113impl_selectable_expression!(today);
114
115operator_allowed!(today, Add, add);
116operator_allowed!(today, Sub, sub);
117
118impl AsExpression<Nullable<Date>> for today {
119    type Expression = Coerce<today, Nullable<Date>>;
120
121    fn as_expression(self) -> Self::Expression {
122        Coerce::new(self)
123    }
124}
diesel/expression/functions/date_and_time.rs

diesel/expression/functions/
date_and_time.rs
