From 049c59d611461d360239a090c8c294dfe3939b53 Mon Sep 17 00:00:00 2001
From: Xin Li <bluer906@gmail.com>
Date: Thu, 18 Jul 2024 10:06:10 +0800
Subject: [PATCH] Fix comments

---
 .../optimizer/src/analyzer/type_coercion.rs    | 18 +++++++++---------
 datafusion/physical-plan/src/filter.rs         |  3 ++-
 datafusion/sqllogictest/test_files/misc.slt    |  1 +
 3 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/datafusion/optimizer/src/analyzer/type_coercion.rs b/datafusion/optimizer/src/analyzer/type_coercion.rs
index 913667eb0342..337492d1a55b 100644
--- a/datafusion/optimizer/src/analyzer/type_coercion.rs
+++ b/datafusion/optimizer/src/analyzer/type_coercion.rs
@@ -47,9 +47,8 @@ use datafusion_expr::type_coercion::{is_datetime, is_utf8_or_large_utf8};
 use datafusion_expr::utils::merge_schema;
 use datafusion_expr::{
     is_false, is_not_false, is_not_true, is_not_unknown, is_true, is_unknown, not,
-    type_coercion, AggregateFunction, AggregateUDF, Expr, ExprSchemable, Filter,
-    LogicalPlan, Operator, ScalarUDF, Signature, WindowFrame, WindowFrameBound,
-    WindowFrameUnits,
+    type_coercion, AggregateFunction, AggregateUDF, Expr, ExprSchemable, LogicalPlan,
+    Operator, ScalarUDF, Signature, WindowFrame, WindowFrameBound, WindowFrameUnits,
 };
 
 use crate::analyzer::AnalyzerRule;
@@ -104,12 +103,13 @@ fn analyze_internal(
     // select t2.c2 from t1 where t1.c1 in (select t2.c1 from t2 where t2.c2=t1.c3)
     schema.merge(external_schema);
 
-    if let LogicalPlan::Filter(Filter {
-        predicate, input, ..
-    }) = &plan
-    {
-        if let Ok(predicate) = predicate.clone().cast_to(&DataType::Boolean, &schema) {
-            plan = LogicalPlan::Filter(Filter::try_new(predicate, Arc::clone(input))?);
+    if let LogicalPlan::Filter(filter) = &mut plan {
+        if let Ok(new_predicate) = filter
+            .predicate
+            .clone()
+            .cast_to(&DataType::Boolean, filter.input.schema())
+        {
+            filter.predicate = new_predicate;
         }
     }
 
diff --git a/datafusion/physical-plan/src/filter.rs b/datafusion/physical-plan/src/filter.rs
index 5455bdc55947..a9d78d059f5c 100644
--- a/datafusion/physical-plan/src/filter.rs
+++ b/datafusion/physical-plan/src/filter.rs
@@ -355,13 +355,14 @@ pub(crate) fn batch_filter(
         .and_then(|v| v.into_array(batch.num_rows()))
         .and_then(|array| {
             Ok(match as_boolean_array(&array) {
+                // apply filter array to record batch
                 Ok(filter_array) => filter_record_batch(batch, filter_array)?,
                 Err(_) => {
                     return internal_err!(
                         "Cannot create filter_array from non-boolean predicates"
                     );
                 }
-            }) // apply filter array to record batch
+            })
         })
 }
 
diff --git a/datafusion/sqllogictest/test_files/misc.slt b/datafusion/sqllogictest/test_files/misc.slt
index 666a69d9169d..9f4710eb9bcc 100644
--- a/datafusion/sqllogictest/test_files/misc.slt
+++ b/datafusion/sqllogictest/test_files/misc.slt
@@ -25,6 +25,7 @@ select 'foo', '', NULL
 ----
 foo (empty) NULL
 
+# Where clause accept NULL literal
 query I
 select 1 where NULL
 ----