diff --git a/src/Interpreters/TableJoin.cpp b/src/Interpreters/TableJoin.cpp
index 7b7ccb689c3..ec5358cf6bc 100644
--- a/src/Interpreters/TableJoin.cpp
+++ b/src/Interpreters/TableJoin.cpp
@@ -512,14 +512,6 @@ TableJoin::createConvertingActions(const ColumnsWithTypeAndName & left_sample_co
 template <typename LeftNamesAndTypes, typename RightNamesAndTypes>
 void TableJoin::inferJoinKeyCommonType(const LeftNamesAndTypes & left, const RightNamesAndTypes & right, bool allow_right)
 {
-    if (strictness() == ASTTableJoin::Strictness::Asof)
-    {
-        if (clauses.size() != 1)
-            throw DB::Exception("ASOF join over multiple keys is not supported", ErrorCodes::NOT_IMPLEMENTED);
-        if (right.back().type->isNullable())
-            throw DB::Exception("ASOF join over right table Nullable column is not implemented", ErrorCodes::NOT_IMPLEMENTED);
-    }
-
     if (!left_type_map.empty() || !right_type_map.empty())
         return;
 
@@ -531,6 +523,15 @@ void TableJoin::inferJoinKeyCommonType(const LeftNamesAndTypes & left, const Rig
     for (const auto & col : right)
         right_types[renamedRightColumnName(col.name)] = col.type;
 
+    if (strictness() == ASTTableJoin::Strictness::Asof)
+    {
+        if (clauses.size() != 1)
+            throw DB::Exception("ASOF join over multiple keys is not supported", ErrorCodes::NOT_IMPLEMENTED);
+
+        auto asof_key_type = right_types.find(clauses.back().key_names_right.back());
+        if (asof_key_type != right_types.end() && asof_key_type->second->isNullable())
+            throw DB::Exception("ASOF join over right table Nullable column is not implemented", ErrorCodes::NOT_IMPLEMENTED);
+    }
 
     forAllKeys(clauses, [&](const auto & left_key_name, const auto & right_key_name)
     {
diff --git a/tests/queries/0_stateless/01428_nullable_asof_join.sql b/tests/queries/0_stateless/01428_nullable_asof_join.sql
index 30e5c51eb1c..e1b00158d68 100644
--- a/tests/queries/0_stateless/01428_nullable_asof_join.sql
+++ b/tests/queries/0_stateless/01428_nullable_asof_join.sql
@@ -109,3 +109,8 @@ FROM (SELECT toUInt8(number) > 0 as pk, toNullable(toUInt8(number)) as dt FROM n
 ASOF JOIN (SELECT 1 as pk, toNullable(0) as dt) b
 ON a.dt >= b.dt AND a.pk = b.pk
 ORDER BY a.dt; -- { serverError 48 }
+
+SELECT *
+FROM (SELECT NULL AS y, 1 AS x, '2020-01-01 10:10:10' :: DateTime64 AS t) AS t1
+ASOF LEFT JOIN (SELECT NULL AS y, 1 AS x, '2020-01-01 10:10:10' :: DateTime64 AS t) AS t2
+ON t1.t <= t2.t AND t1.x == t2.x FORMAT Null;