diff --git a/backends-clickhouse/src/test/scala/org/apache/gluten/execution/GlutenClickHouseTPCHSuite.scala b/backends-clickhouse/src/test/scala/org/apache/gluten/execution/GlutenClickHouseTPCHSuite.scala
index b4cefc3a77a2..a853cf7e4c95 100644
--- a/backends-clickhouse/src/test/scala/org/apache/gluten/execution/GlutenClickHouseTPCHSuite.scala
+++ b/backends-clickhouse/src/test/scala/org/apache/gluten/execution/GlutenClickHouseTPCHSuite.scala
@@ -427,6 +427,14 @@ class GlutenClickHouseTPCHSuite extends MergeTreeSuite {
 
   }
 
+  test("var_samp returns null instead of NaN") {
+    val sql1 = "select var_samp(id) from range(1)"
+    val sql2 = "select covar_samp(id, id) from range(1)"
+
+    compareResultsAgainstVanillaSpark(sql1, true, { _ => })
+    compareResultsAgainstVanillaSpark(sql2, true, { _ => })
+  }
+
   test("existence join") {
     spark.sql("create table t1(a int, b int) using parquet")
     spark.sql("create table t2(a int, b int) using parquet")
diff --git a/cpp-ch/local-engine/Parser/AggregateFunctionParser.cpp b/cpp-ch/local-engine/Parser/AggregateFunctionParser.cpp
index 696f5352f200..5bc055d08e6c 100644
--- a/cpp-ch/local-engine/Parser/AggregateFunctionParser.cpp
+++ b/cpp-ch/local-engine/Parser/AggregateFunctionParser.cpp
@@ -219,7 +219,9 @@ const DB::ActionsDAG::Node * AggregateFunctionParser::convertNodeTypeIfNeeded(
 const DB::ActionsDAG::Node * AggregateFunctionParser::convertNanToNullIfNeed(
     const CommonFunctionInfo & func_info, const DB::ActionsDAG::Node * func_node, DB::ActionsDAG & actions_dag) const
 {
-    if (getCHFunctionName(func_info) != "corr" || !func_node->result_type->isNullable())
+    const auto function_name = getCHFunctionName(func_info);
+    if ((function_name != "corr" && function_name != "varSamp" && function_name != "covarSamp")
+        || !func_node->result_type->isNullable())
         return func_node;
 
     /// result is nullable.