From 882db06dc89643d370fab66ba2d84381d854b3b7 Mon Sep 17 00:00:00 2001
From: Mingj <mingji_han@outlook.com>
Date: Wed, 13 Oct 2021 17:46:49 -0400
Subject: [PATCH] refactor(binder): support BoundTableRef enum

---
 src/binder/statement/select.rs | 23 ++++++++++++++++-------
 src/binder/table_ref/mod.rs    | 19 +++++++++++++------
 src/logical_plan/select.rs     | 18 +++++++++++++-----
 3 files changed, 42 insertions(+), 18 deletions(-)

diff --git a/src/binder/statement/select.rs b/src/binder/statement/select.rs
index 9911cbbc..0465b284 100644
--- a/src/binder/statement/select.rs
+++ b/src/binder/statement/select.rs
@@ -1,4 +1,5 @@
 use super::*;
+use crate::binder::BoundTableRef;
 use crate::parser::{Query, SelectItem, SetExpr};
 
 #[derive(Debug, PartialEq, Clone)]
@@ -30,6 +31,11 @@ impl Binder {
         };
         // Bind table ref
         let mut from_table = vec![];
+        // We don't support cross join now.
+        // The cross join will have multiple TableWithJoin in "from" struct.
+        // Other types of join will onyl have one TableWithJoin in "from" struct.
+        assert!(select.from.len() <= 1);
+
         for table_ref in select.from.iter() {
             let table_ref = self.bind_table_ref(&table_ref.relation)?;
             from_table.push(table_ref);
@@ -65,12 +71,15 @@ impl Binder {
 
         // Add referred columns for base table reference
         for table_ref in from_table.iter_mut() {
-            table_ref.column_ids = self
-                .context
-                .column_ids
-                .get(&table_ref.table_name)
-                .unwrap()
-                .clone();
+            match table_ref {
+                BoundTableRef::BaseTableRef {
+                    ref_id: _,
+                    table_name,
+                    column_ids,
+                } => {
+                    *column_ids = self.context.column_ids.get(table_name).unwrap().clone();
+                }
+            }
         }
 
         Ok(Box::new(BoundSelect {
@@ -136,7 +145,7 @@ mod tests {
                         return_type: Some(DataTypeKind::Int.not_null()),
                     },
                 ],
-                from_table: vec![BoundTableRef {
+                from_table: vec![BoundTableRef::BaseTableRef {
                     ref_id: TableRefId::new(0, 0, 0),
                     table_name: "t".into(),
                     column_ids: vec![1, 0],
diff --git a/src/binder/table_ref/mod.rs b/src/binder/table_ref/mod.rs
index 62713a15..a5da1f3a 100644
--- a/src/binder/table_ref/mod.rs
+++ b/src/binder/table_ref/mod.rs
@@ -1,11 +1,12 @@
 use super::*;
 use crate::parser::TableFactor;
-
 #[derive(Debug, PartialEq, Clone)]
-pub struct BoundTableRef {
-    pub ref_id: TableRefId,
-    pub table_name: String,
-    pub column_ids: Vec<ColumnId>,
+pub enum BoundTableRef {
+    BaseTableRef {
+        ref_id: TableRefId,
+        table_name: String,
+        column_ids: Vec<ColumnId>,
+    },
 }
 
 impl Binder {
@@ -33,12 +34,18 @@ impl Binder {
                 self.context
                     .column_ids
                     .insert(table_name.into(), Vec::new());
-                Ok(BoundTableRef {
+                Ok(BoundTableRef::BaseTableRef {
                     ref_id,
                     table_name: table_name.into(),
                     column_ids: vec![],
                 })
             }
+            TableFactor::NestedJoin(table_with_joins) => {
+                let bounded_table_ref = self.bind_table_ref(&table_with_joins.relation)?;
+                // We only support cross join now.
+                assert_eq!(table_with_joins.joins.len(), 0);
+                Ok(bounded_table_ref)
+            }
             _ => panic!("bind table ref"),
         }
     }
diff --git a/src/logical_plan/select.rs b/src/logical_plan/select.rs
index 4ed31503..244935e7 100644
--- a/src/logical_plan/select.rs
+++ b/src/logical_plan/select.rs
@@ -1,14 +1,22 @@
 use super::*;
-use crate::binder::BoundSelect;
+use crate::binder::{BoundSelect, BoundTableRef};
 
 impl LogicalPlaner {
     pub fn plan_select(&self, stmt: Box<BoundSelect>) -> Result<LogicalPlan, LogicalPlanError> {
         let mut plan = LogicalPlan::Dummy;
         if let Some(table_ref) = stmt.from_table.get(0) {
-            plan = LogicalPlan::SeqScan(LogicalSeqScan {
-                table_ref_id: table_ref.ref_id,
-                column_ids: table_ref.column_ids.clone(),
-            });
+            match table_ref {
+                BoundTableRef::BaseTableRef {
+                    ref_id,
+                    table_name: _,
+                    column_ids,
+                } => {
+                    plan = LogicalPlan::SeqScan(LogicalSeqScan {
+                        table_ref_id: *ref_id,
+                        column_ids: column_ids.to_vec(),
+                    });
+                }
+            }
         }
         if let Some(expr) = stmt.where_clause {
             plan = LogicalPlan::Filter(LogicalFilter {