risingwave_frontend/binder/relation/
subquery.rs

1// Copyright 2025 RisingWave Labs
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15use risingwave_sqlparser::ast::{Query, TableAlias};
16
17use crate::binder::statement::RewriteExprsRecursive;
18use crate::binder::{Binder, BoundQuery, UNNAMED_SUBQUERY};
19use crate::error::Result;
20
21#[derive(Debug, Clone)]
22pub struct BoundSubquery {
23    pub query: BoundQuery,
24    pub lateral: bool,
25}
26
27impl RewriteExprsRecursive for BoundSubquery {
28    fn rewrite_exprs_recursive(&mut self, rewriter: &mut impl crate::expr::ExprRewriter) {
29        self.query.rewrite_exprs_recursive(rewriter);
30    }
31}
32
33impl Binder {
34    /// Binds a subquery using [`bind_query`](Self::bind_query), which will use a new empty
35    /// [`BindContext`](crate::binder::BindContext) for it.
36    ///
37    /// After finishing binding, we update the current context with the output of the subquery.
38    pub(super) fn bind_subquery_relation(
39        &mut self,
40        query: Query,
41        alias: Option<TableAlias>,
42        lateral: bool,
43    ) -> Result<BoundSubquery> {
44        let query = self.bind_query(query)?;
45        let sub_query_id = self.next_subquery_id();
46
47        self.bind_table_to_context(
48            query
49                .body
50                .schema()
51                .fields
52                .iter()
53                .map(|f| (false, f.clone())),
54            format!("{}_{}", UNNAMED_SUBQUERY, sub_query_id),
55            alias,
56        )?;
57        Ok(BoundSubquery { query, lateral })
58    }
59}
risingwave_frontend/binder/relation/subquery.rs

risingwave_frontend/binder/relation/
subquery.rs
