refine

Signed-off-by: TennyZhuang <[email protected]>

src/frontend/src/binder/bind_context.rs

@@ -92,6 +92,13 @@ pub enum BindingCteState {
     Bound { query: BoundQuery },
 }
 
+#[derive(Clone, Debug)]
+pub struct BindingCte {
+    pub share_id: ShareId,
+    pub state: BindingCteState,
+    pub alias: TableAlias,
+}
+
 #[derive(Default, Debug, Clone)]
 pub struct BindContext {
     // Columns of all tables.
@@ -106,7 +113,7 @@ pub struct BindContext {
     pub column_group_context: ColumnGroupContext,
     /// Map the cte's name to its binding state.
     /// The `ShareId` of the value is used to help the planner identify the share plan.
-    pub cte_to_relation: HashMap<String, Rc<RefCell<(ShareId, BindingCteState, TableAlias)>>>,
+    pub cte_to_relation: HashMap<String, Rc<RefCell<BindingCte>>>,
     /// Current lambda functions's arguments
     pub lambda_args: Option<HashMap<String, (usize, DataType)>>,
 }

src/frontend/src/binder/query.rs

@@ -27,6 +27,7 @@ use thiserror_ext::AsReport;
 use super::bind_context::BindingCteState;
 use super::statement::RewriteExprsRecursive;
 use super::BoundValues;
+use crate::binder::bind_context::BindingCte;
 use crate::binder::{Binder, BoundSetExpr};
 use crate::error::{ErrorCode, Result};
 use crate::expr::{CorrelatedId, Depth, ExprImpl, ExprRewriter};
@@ -333,11 +334,11 @@ impl Binder {
                     .context
                     .cte_to_relation
                     .entry(table_name)
-                    .insert_entry(Rc::new(RefCell::new((
+                    .insert_entry(Rc::new(RefCell::new(BindingCte {
                         share_id,
-                        BindingCteState::Init,
+                        state: BindingCteState::Init,
                         alias,
-                    ))))
+                    })))
                     .get()
                     .clone();
 
@@ -346,9 +347,11 @@ impl Binder {
                 }
 
                 // We assume `left` is base term, otherwise the implementation may be very hard.
+                // The behavior is same as PostgreSQL.
+                // https://www.postgresql.org/docs/16/sql-select.html#:~:text=the%20recursive%20self%2Dreference%20must%20appear%20on%20the%20right%2Dhand%20side%20of%20the%20UNION
                 let bound_base = self.bind_set_expr(*left)?;
 
-                entry.borrow_mut().1 = BindingCteState::BaseResolved {
+                entry.borrow_mut().state = BindingCteState::BaseResolved {
                     schema: bound_base.schema().clone(),
                 };
 
@@ -366,16 +369,16 @@ impl Binder {
                     extra_order_exprs: vec![],
                 };
 
-                entry.borrow_mut().1 = BindingCteState::Bound { query: bound_query };
+                entry.borrow_mut().state = BindingCteState::Bound { query: bound_query };
             } else {
                 let bound_query = self.bind_query(query)?;
                 self.context.cte_to_relation.insert(
                     table_name,
-                    Rc::new(RefCell::new((
+                    Rc::new(RefCell::new(BindingCte {
                         share_id,
-                        BindingCteState::Bound { query: bound_query },
+                        state: BindingCteState::Bound { query: bound_query },
                         alias,
-                    ))),
+                    })),
                 );
             }
         }

src/frontend/src/binder/relation/mod.rs

@@ -28,7 +28,7 @@ use thiserror_ext::AsReport;
 use self::cte_ref::BoundBackCteRef;
 use super::bind_context::ColumnBinding;
 use super::statement::RewriteExprsRecursive;
-use crate::binder::bind_context::BindingCteState;
+use crate::binder::bind_context::{BindingCte, BindingCteState};
 use crate::binder::Binder;
 use crate::error::{ErrorCode, Result, RwError};
 use crate::expr::{ExprImpl, InputRef};
@@ -347,7 +347,11 @@ impl Binder {
         {
             // Handles CTE
 
-            let (share_id, cte_state, mut original_alias) = item.deref().borrow().clone();
+            let BindingCte {
+                share_id,
+                state: cte_state,
+                alias: mut original_alias,
+            } = item.deref().borrow().clone();
             debug_assert_eq!(original_alias.name.real_value(), table_name); // The original CTE alias ought to be its table name.
 
             if let Some(from_alias) = alias {