diesel/query_builder/insert_statement/
insert_from_select.rs

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1use crate::expression::{Expression, NonAggregate, SelectableExpression};
2use crate::insertable::*;
3use crate::query_builder::*;
4use crate::query_source::Table;
5
6/// Represents `(Columns) SELECT FROM ...` for use in an `INSERT` statement
7#[derive(Debug, Clone, Copy, QueryId)]
8pub struct InsertFromSelect<Select, Columns> {
9    pub(in crate::query_builder) query: Select,
10    pub(in crate::query_builder) columns: Columns,
11}
12
13impl<Select, Columns> InsertFromSelect<Select, Columns> {
14    /// Construct a new `InsertFromSelect` where the target column list is
15    /// `T::AllColumns`.
16    pub fn new<T>(query: Select) -> Self
17    where
18        T: Table<AllColumns = Columns>,
19        Columns: SelectableExpression<T> + NonAggregate,
20    {
21        Self {
22            query,
23            columns: T::all_columns(),
24        }
25    }
26
27    /// Replace the target column list
28    pub fn with_columns<C>(self, columns: C) -> InsertFromSelect<Select, C> {
29        InsertFromSelect {
30            query: self.query,
31            columns,
32        }
33    }
34}
35
36impl<DB, Select, Columns> CanInsertInSingleQuery<DB> for InsertFromSelect<Select, Columns>
37where
38    DB: Backend,
39{
40    fn rows_to_insert(&self) -> Option<usize> {
41        None
42    }
43}
44
45impl<DB, Select, Columns> QueryFragment<DB> for InsertFromSelect<Select, Columns>
46where
47    DB: Backend,
48    Columns: ColumnList + Expression,
49    Select: Query<SqlType = Columns::SqlType> + QueryFragment<DB>,
50{
51    fn walk_ast<'b>(&'b self, mut out: AstPass<'_, 'b, DB>) -> QueryResult<()> {
52        out.push_sql("(");
53        self.columns.walk_ast(out.reborrow())?;
54        out.push_sql(") ");
55        self.query.walk_ast(out.reborrow())?;
56        Ok(())
57    }
58}
59
60impl<Select, Columns> UndecoratedInsertRecord<Columns::Table> for InsertFromSelect<Select, Columns>
61where
62    Columns: ColumnList + Expression,
63    Select: Query<SqlType = Columns::SqlType>,
64{
65}
diesel/query_builder/insert_statement/insert_from_select.rs

diesel/query_builder/insert_statement/
insert_from_select.rs
