diff --git a/be/src/exprs/bitmap_function.cpp b/be/src/exprs/bitmap_function.cpp
index 1d4fc4df47..7254dc3a45 100644
--- a/be/src/exprs/bitmap_function.cpp
+++ b/be/src/exprs/bitmap_function.cpp
@@ -190,7 +190,7 @@ StringVal BitmapFunctions::to_bitmap_with_check(doris_udf::FunctionContext* ctx,
                   "18446744073709551615 currently, cannot load negative values to column with"
                   " to_bitmap MV on it.";
             ctx->set_error(ss.str().c_str());
-            return StringVal::null();
+            return serialize(ctx, nullptr);
         }
     }
 
diff --git a/be/src/vec/exec/vunion_node.cpp b/be/src/vec/exec/vunion_node.cpp
index 0bf6b2f826..e3343e25de 100644
--- a/be/src/vec/exec/vunion_node.cpp
+++ b/be/src/vec/exec/vunion_node.cpp
@@ -197,7 +197,9 @@ Status VUnionNode::get_next_const(RuntimeState* state, Block* block) {
                                                                                 &result_list[i]));
         }
         tmp_block.erase_not_in(result_list);
-        mblock.merge(tmp_block);
+        if (tmp_block.rows() > 0) {
+            mblock.merge(tmp_block);
+        }
     }
 
     if (!mem_reuse) {
diff --git a/gensrc/script/doris_builtins_functions.py b/gensrc/script/doris_builtins_functions.py
index 4715372acf..5c14145853 100755
--- a/gensrc/script/doris_builtins_functions.py
+++ b/gensrc/script/doris_builtins_functions.py
@@ -2478,7 +2478,7 @@ visible_functions = [
         '_ZN5doris15BitmapFunctions9to_bitmapEPN9doris_udf15FunctionContextERKNS1_9StringValE',
         '', '', 'vec', 'ALWAYS_NOT_NULLABLE'],
     [['to_bitmap_with_check'], 'BITMAP', ['STRING'],
-        '_ZN5doris15BitmapFunctions9to_bitmapEPN9doris_udf15FunctionContextERKNS1_9StringValE',
+        '_ZN5doris15BitmapFunctions20to_bitmap_with_checkEPN9doris_udf15FunctionContextERKNS1_9StringValE',
         '', '', 'vec', 'ALWAYS_NOT_NULLABLE'],
     [['bitmap_hash'], 'BITMAP', ['STRING'],
         '_ZN5doris15BitmapFunctions11bitmap_hash64EPN9doris_udf15FunctionContextERKNS1_9StringValE',