diff --git a/core/translate/emitter.rs b/core/translate/emitter.rs
index 9482567b4..cb2a4cb0e 100644
--- a/core/translate/emitter.rs
+++ b/core/translate/emitter.rs
@@ -1150,11 +1150,11 @@ fn open_loop(
 fn try_index_cover(
     program: &mut ProgramBuilder,
     related_columns: &BTreeSet<ColumnBinding>,
-    table_reference: &BTreeTableReference,
+    table_reference: &TableReference,
     index_cursor_id: CursorID,
     table_cursor_id: CursorID,
 ) -> bool {
-    let BTreeTableReference {
+    let TableReference {
         table, table_index, ..
     } = table_reference;
 
@@ -1167,7 +1167,7 @@ fn try_index_cover(
             index_column_map.insert(pos, i);
         }
         if let Some(pos) = table
-            .columns
+            .columns()
             .iter()
             .position(|column| column.is_rowid_alias)
         {
diff --git a/core/translate/optimizer.rs b/core/translate/optimizer.rs
index 5480e82b2..70b92b2fc 100644
--- a/core/translate/optimizer.rs
+++ b/core/translate/optimizer.rs
@@ -1,6 +1,12 @@
 use std::collections::BTreeSet;
 use std::rc::Rc;
 
+use super::plan::{
+    get_table_ref_bitmask_for_ast_expr, get_table_ref_bitmask_for_operator, Aggregate,
+    ColumnBinding, DeletePlan, Direction, GroupBy, IterationDirection, Plan, ResultSetColumn,
+    Search, SelectPlan, SourceOperator, TableReference, TableReferenceType,
+};
+use crate::translate::optimizer;
 use crate::{schema::Index, Result};
 use sqlite3_parser::ast;
 use sqlite3_parser::ast::{
@@ -8,12 +14,6 @@ use sqlite3_parser::ast::{
     SelectTable, SortedColumn, Window,
 };
 
-use super::plan::{
-    get_table_ref_bitmask_for_ast_expr, get_table_ref_bitmask_for_operator, Aggregate,
-    TableReference, TableReferenceType, ColumnBinding, DeletePlan, Direction, GroupBy, IterationDirection, Plan,
-    ResultSetColumn, Search, SelectPlan, SourceOperator,
-};
-
 pub fn optimize_plan(plan: &mut Plan) -> Result<()> {
     match plan {
         Plan::Select(plan) => optimize_select_plan(plan),
@@ -666,7 +666,7 @@ fn related_columns(
     order_by: &Option<Vec<(ast::Expr, Direction)>>,
     aggregates: &[Aggregate],
     related_columns: &mut BTreeSet<ColumnBinding>,
-    referenced_tables: &[BTreeTableReference],
+    referenced_tables: &[TableReference],
 ) -> Result<()> {
     source_related_columns(operator, related_columns, referenced_tables)?;
     for column in result_columns.iter() {
@@ -706,7 +706,7 @@ fn related_columns(
 fn source_related_columns(
     source_operator: &SourceOperator,
     related_columns: &mut BTreeSet<ColumnBinding>,
-    referenced_tables: &[BTreeTableReference],
+    referenced_tables: &[TableReference],
 ) -> Result<()> {
     match source_operator {
         SourceOperator::Join {
@@ -747,7 +747,27 @@ fn source_related_columns(
                 }
             }
         }
-        SourceOperator::Nothing => (),
+        SourceOperator::Nothing { .. } => (),
+        SourceOperator::Subquery {
+            plan, predicates, ..
+        } => {
+            optimizer::related_columns(
+                &plan.source,
+                &plan.result_columns,
+                &plan.where_clause,
+                &plan.group_by,
+                &plan.order_by,
+                &plan.aggregates,
+                related_columns,
+                &plan.referenced_tables,
+            )?;
+
+            if let Some(predicates) = predicates {
+                for expr in predicates {
+                    expr_related_columns(expr, related_columns, referenced_tables)?;
+                }
+            }
+        }
     }
 
     Ok(())
@@ -756,7 +776,7 @@ fn source_related_columns(
 fn from_clause_related_columns(
     from: &FromClause,
     related_columns: &mut BTreeSet<ColumnBinding>,
-    referenced_tables: &[BTreeTableReference],
+    referenced_tables: &[TableReference],
 ) -> Result<()> {
     if let Some(select_table) = &from.select {
         select_table_related_columns(select_table, related_columns, referenced_tables)?;
@@ -782,7 +802,7 @@ fn from_clause_related_columns(
 fn select_table_related_columns(
     select_table: &SelectTable,
     related_columns: &mut BTreeSet<ColumnBinding>,
-    referenced_tables: &[BTreeTableReference],
+    referenced_tables: &[TableReference],
 ) -> Result<()> {
     match select_table {
         SelectTable::TableCall(_, exprs, _) => {
@@ -807,7 +827,7 @@ fn select_table_related_columns(
 fn one_select_related_columns(
     one_select: &OneSelect,
     related_columns: &mut BTreeSet<ColumnBinding>,
-    referenced_tables: &[BTreeTableReference],
+    referenced_tables: &[TableReference],
 ) -> Result<()> {
     match one_select {
         OneSelect::Select {
@@ -829,14 +849,14 @@ fn one_select_related_columns(
                     ResultColumn::TableStar(table_name) => {
                         let Some(table_pos) = referenced_tables
                             .iter()
-                            .position(|table| table.table.name == table_name.0)
+                            .position(|table| table.table.get_name() == table_name.0)
                         else {
                             crate::bail_corrupt_error!(
                                 "Optimize error: no such table: {}",
                                 table_name
                             )
                         };
-                        for i in 0..referenced_tables[table_pos].table.columns.len() {
+                        for i in 0..referenced_tables[table_pos].table.columns().len() {
                             related_columns.insert(ColumnBinding {
                                 table: table_pos,
                                 column: i,
@@ -880,7 +900,7 @@ fn one_select_related_columns(
 fn select_related_columns(
     select: &Select,
     related_columns: &mut BTreeSet<ColumnBinding>,
-    referenced_tables: &[BTreeTableReference],
+    referenced_tables: &[TableReference],
 ) -> Result<()> {
     let Select {
         body: SelectBody { select, compounds },
@@ -910,7 +930,7 @@ fn select_related_columns(
 fn expr_related_columns(
     expr: &ast::Expr,
     related_columns: &mut BTreeSet<ColumnBinding>,
-    referenced_tables: &[BTreeTableReference],
+    referenced_tables: &[TableReference],
 ) -> Result<()> {
     match expr {
         ast::Expr::Between {
@@ -1041,7 +1061,7 @@ fn expr_related_columns(
 fn window_related_columns(
     window: &Window,
     related_columns: &mut BTreeSet<ColumnBinding>,
-    referenced_tables: &[BTreeTableReference],
+    referenced_tables: &[TableReference],
 ) -> Result<()> {
     if let Some(partition_by) = &window.partition_by {
         for expr in partition_by {
@@ -1070,10 +1090,10 @@ fn window_related_columns(
 #[inline]
 fn full_related_columns(
     related_columns: &mut BTreeSet<ColumnBinding>,
-    referenced_tables: &[BTreeTableReference],
+    referenced_tables: &[TableReference],
 ) {
     for (table_pos, reference_table) in referenced_tables.iter().enumerate() {
-        for i in 0..reference_table.table.columns.len() {
+        for i in 0..reference_table.table.columns().len() {
             related_columns.insert(ColumnBinding {
                 table: table_pos,
                 column: i,
@@ -1086,7 +1106,7 @@ fn full_related_columns(
 fn order_by_related_columns(
     order_by: &Option<Vec<SortedColumn>>,
     related_columns: &mut BTreeSet<ColumnBinding>,
-    referenced_tables: &[BTreeTableReference],
+    referenced_tables: &[TableReference],
 ) -> Result<()> {
     if let Some(sort_columns) = order_by {
         for column in sort_columns {
diff --git a/core/translate/plan.rs b/core/translate/plan.rs
index 989febf03..dcc976e90 100644
--- a/core/translate/plan.rs
+++ b/core/translate/plan.rs
@@ -11,18 +11,12 @@ use crate::{
     vdbe::BranchOffset,
     Result,
 };
-use core::fmt;
-use sqlite3_parser::ast;
-use std::cmp::Ordering;
-use std::collections::BTreeSet;
-use std::{
-    fmt::{Display, Formatter},
-    rc::Rc,
-};
 use crate::{
     schema::{PseudoTable, Type},
     translate::plan::Plan::{Delete, Select},
 };
+use std::cmp::Ordering;
+use std::collections::BTreeSet;
 
 #[derive(Debug, Clone)]
 pub struct ResultSetColumn {
@@ -45,7 +39,7 @@ pub enum Plan {
     Delete(DeletePlan),
 }
 
-#[derive(Debug, Eq, PartialEq)]
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
 pub struct ColumnBinding {
     pub table: usize,
     pub column: usize,