From f1087f5c042ea093c6fd4d700dcecd8d2da6bf4a Mon Sep 17 00:00:00 2001
From: Yevhenii Melnyk <melnyk.yevhenii@gmail.com>
Date: Thu, 2 Feb 2023 10:38:52 +0100
Subject: [PATCH] Compare NULL types

---
 .../pg_compat/pg_compat_type_coercion.slt           | 13 +++++--------
 datafusion/expr/src/type_coercion/binary.rs         |  6 +++---
 2 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/datafusion/core/tests/sqllogictests/test_files/pg_compat/pg_compat_type_coercion.slt b/datafusion/core/tests/sqllogictests/test_files/pg_compat/pg_compat_type_coercion.slt
index aee35e08f59f1..4a85a835c0790 100644
--- a/datafusion/core/tests/sqllogictests/test_files/pg_compat/pg_compat_type_coercion.slt
+++ b/datafusion/core/tests/sqllogictests/test_files/pg_compat/pg_compat_type_coercion.slt
@@ -95,20 +95,17 @@ select pg_typeof(false or true), pg_typeof(true or false);
 bool bool
 
 
-# TODO: run for DataFusion as well after #4335
-onlyif postgres
 query ??
 select null and null, null or null;
 ----
 NULL NULL
 
 
-# TODO: uncomment after #4335
-#onlyif DataFusion
-#query ??
-#select arrow_typeof(null and null), arrow_typeof(null or null);
-#----
-#Boolean Boolean
+onlyif DataFusion
+query ??
+select arrow_typeof(null and null), arrow_typeof(null or null);
+----
+Boolean Boolean
 
 
 onlyif postgres
diff --git a/datafusion/expr/src/type_coercion/binary.rs b/datafusion/expr/src/type_coercion/binary.rs
index d2923c8dbfae7..08e0aac251ea6 100644
--- a/datafusion/expr/src/type_coercion/binary.rs
+++ b/datafusion/expr/src/type_coercion/binary.rs
@@ -100,7 +100,7 @@ pub fn coerce_types(
         Operator::And | Operator::Or => match (lhs_type, rhs_type) {
             // logical binary boolean operators can only be evaluated in bools or nulls
             (DataType::Boolean, DataType::Boolean) => Some(DataType::Boolean),
-            (DataType::Null, DataType::Null) => Some(DataType::Null),
+            (DataType::Null, DataType::Null) => Some(DataType::Boolean),
             (DataType::Boolean, DataType::Null) | (DataType::Null, DataType::Boolean) => {
                 Some(DataType::Boolean)
             }
@@ -1147,13 +1147,13 @@ mod tests {
             DataType::Null,
             DataType::Null,
             Operator::Or,
-            DataType::Null
+            DataType::Boolean
         );
         test_coercion_binary_rule!(
             DataType::Null,
             DataType::Null,
             Operator::And,
-            DataType::Null
+            DataType::Boolean
         );
         test_coercion_binary_rule!(
             DataType::Null,